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  • 1990-1994  (2,210)
  • 1992  (2,210)
  • Analytical Chemistry and Spectroscopy  (1,522)
  • Chemical Engineering  (688)
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  • 1990-1994  (2,210)
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Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Simultaneous acoustic wave propagation and dynamic mechanical analysis of curing of thermoset resinsPart of this work has been presented at the Golden Gate Polymer Forum, Asilomar Conference, in March 1990. (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 182-190 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A study of simultaneous acoustic and rheometric (dynamic mechanical) measurements of the epoxy curing process is undertaken to assess the validity of using acoustic cure-monitoring sensors for process control. Our results demonstrate that the acoustic technique provides a sensitive means for monitoring the cure of neat epoxy over the entire cure cycle. The acoustic modulus calculated from the shear velocity qualitatively tracks the mechanically measured dynamic modulus and correctly ranks the stiffness of two epoxy compositions. When the frequency difference is accounted for, using time-temperature superposition of the dynamic mechanical measurements, quantitative agreement between the acoustic and mechanical moduli for fully cured epoxy resins is also quite good.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320304
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  • 2
    Electronic Resource
    Electronic Resource
    The grafting of maleic anhydride on high density polyethylene in an extruder (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 467-474 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The grafting of maleic anhydride (MAH) on high density polyethylene in a counter-rotating twin screw extruder has been studied. As the reaction kinetics appear to be affected by mass transfer, good micro mixing in the extruder is important. Due to the competing mechanisms of increasing mixing and decreasing residence times at increasing screw speed, and due to the complicated reaction scheme, various non-linearities exist that are prohibitive for simple optimization rules. The interaction diagram presented in this paper for a twin screw extruder as a MAH grafting reactor can be used for better understanding of the influence of the extruder parameters on the reaction process.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320703
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  • 3
    Electronic Resource
    Electronic Resource
    Gear pump assisted extrusion (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 488-493 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Gear pump assisted extrusion is becoming popular in the plastics processing industries. The growth has been tremendous since 1980. In this study, the benefits of gear pump assisted extrusion, especially in single screw applications, is critically reviewed, and a method of predicting the operational conditions of the gear pump assisted extrusion system is discussed. Further, shortening the length to diameter ratio of the extruder in gear pump assisted extrusion was analyzed and found to produce a reduction in energy consumption, provided melting is completed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320706
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  • 4
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320801
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  • 5
    Electronic Resource
    Electronic Resource
    The measurement of thermal stress distributions along the flow path in injection-molded flat plates (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 506-515 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Internal stresses in injection-molded parts are the result of thermal, flow, and pressure histories. Internal stresses can be roughly divided into thermal and flow-induced stresses. In this paper, a modified layer-removal method is presented to determine thermal stress distributions in injection-molded flat plates. With this method, the curvature of a rectangular specimen is determined after the removal of a layer from one surface. This curvature is converted into a stress via a mathematical relation, originally derived by Treuting and Read. By determining the local curvatures after successive layer removals, stress distributions along the flow path were obtained within a single specimen. Validation of this modified layer-removal method is described. A good reproductibility was obtained. The method can be regarded as semi-quantitative. Flat plates were injection-molded from three amorphous polymers: polystyrene, polycarbonate, and a polyphenylene ether/high-impact polystyrene blend. In general, the flat-plate cross-section shows a three-region stress distribution with a tensile stress region both at the surface and in the core of the flat plate and an intermediate region with compressive stresses. The modified layer-removal method was used to determine influences of mold temperature, annealing treatment, and pressure history on the thermal stress distributions. Increasing mold temperature results in a decreasing overall stress level, while the compressive stress region shifts to the surface. An annealing treatment significantly reduces the overall stress level, without affecting the stress pattern. Stress distributions along the flow path were influenced by the varying pressure histories from the entrance to the end of the mold cavity. The various features of the stress profiles are explained by the influence of the pressure decay rate in the injection-molding process.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320708
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of gel formation in imidazole-catalyzed epoxies (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 529-534 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The network formation processes for imidazole-cured epoxy resins were examined by relating the reaction chemistry and the physical properties during cure. Network formation models were developed based on kinetic studies and the laws of conditional probability. These models were used to predict the weight-average molecular weight, the gel point, and the sol fraction as a function of the resin composition and the processing conditions. Rheological and extraction experiments were conducted to confirm the model results and to develop criteria for identifying the gel point.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320804
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  • 7
    Electronic Resource
    Electronic Resource
    Catalysis and kinetics of cyclotrimerization of cyanate ester resin systems (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 535-541 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The kinetics of cyclotrimerization and the thermal stability of bisphenol Abased cyanate ester resin systems were determined using Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry. The bisphenol A dicyanate was cured with 4 phr nonylphenol and with the octoates of zinc and manganese, and cobalt acetylacetonate at concentrations ranging from 0 to 750 ppm metal. An empirical rate law was used to predict the cyanate concentration profiles. The observed reaction rate showed a first-order dependenće on the initial metal concentration and a second-order dependence on the cyanate concentration in the kinetically controlled regime. For the uncatalyzed systems, the kinetics was described by a second-order autocatalytic model. The thermal stability of the network was found to be dependent on the catalyst concentration for the zinc catalysts. For the samples cured with manganese, no effect of concentration on the thermal stability was observed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320805
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  • 8
    Electronic Resource
    Electronic Resource
    Improving adhesion between thin chromium film and polyimide substrate by Ar+ irradiation (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 558-566 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Ar+ irradiation and annealing at an elevated temperature are used to improve the adhesion of deposited Cr thin films by vacuum evaporation onto polyimide (PI) substrates. The Ar+ ions of 50 and 200 keV and various Ar+ doses ranging from 1 × 1013 to 2 × 1016 ions/cm2 are chosen for the experiments, after many preliminary trials. The surface analyses are conducted employing Rutherford Backscattering Spectroscopy (RBS), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), and Scanning electron microscopy (SEM). Ar+ irradiation produces an interfacial layer of about 100 Å (10 nm) thick in which Cr particles and PI molecules are physically mixed and chemically bonded. The chemical bonds of Cr—O and a trace of Cr≡C are observed by XPS and FTIR. Impact-wear tests are also conducted in order to determine the effects of the Ar+ irradiation on the wear property of a Cr/PI system. A significant increase in the property is observed and the increase appears to be a function of the degree of adhesion of the Cr film to the PI substrate.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320807
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  • 9
    Electronic Resource
    Electronic Resource
    Preface (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 581-581 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320902
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  • 10
    Electronic Resource
    Electronic Resource
    CO2 laser welding of polymers (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 582-585 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Deep penetration welding of polymers can be carried out at high speed with relatively low laser power. This results from an efficient coupling CO2 laser radiation to polymers that leads to volume heating. A brief review of energy coupling and heat transfer effects in polymers under CO2 laser welding conditions is given. Some examples of low power (10 to 100 watt) CO2 welding of polypropylene and polyethylene at depths of up to 1.5 cm are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320903
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  • 11
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320401
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  • 12
    Electronic Resource
    Electronic Resource
    Simulation of polymer flow through a coat-hanger die: A comparison of two numerical approaches (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 206-212 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Coat-hanger dies are commonly used for the extrusion of plastic sheets and films. To describe the flow of a molten polymer through a coat-hanger die, a two-dimensional approach is necessary. Moreover, the thermal effects, which play an important role in the flow distribution, have to be taken into account. In this paper, two numerical models for the simulation of coat-hanger dies are described and compared. These models differ mainly in the simplifying assumptions used and in the treatment of the thermal problem. The simulations obtained with the two models were compared with each other and with experimental data. The discrepancies between the two models can be explained by the different theoretical treatments.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320307
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  • 13
    Electronic Resource
    Electronic Resource
    A general non-isothermal model for one-dimensional multilayer coextrusion flows (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 213-220 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A general computation of multilayer coextrusion flow in a flat die geometry is presented. For any given number of layers of different polymers, characterized by their thermal and rheological behaviors, the model permits computation of velocity and temperature fields along the flow in constant or slightly varying geometries. The influence of different operating parameters (wall regulation temperature, flow rate, initial temperatures) on the interface positions and temperature evolutions is evaluated. Theoretical predictions of interface positions are in agreement with experiments carried out on an industrial multimanifold flat die.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320308
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  • 14
    Electronic Resource
    Electronic Resource
    Resin flow through fiber beds during composite manufacturing processes. Part I: Review of newtonian flow through fiber beds (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 221-230 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A critical part of any master model used to simulate or control a composite material manufacturing process is the description of resin flow through the fiber bed. We present here a review of both theoretical and experimental studies of fluid flow through porous media, including fiber beds. For the practical porosity range of interest in continuous fiber composites processing (0.3〈 ∊ 〈 0.6), the permeability cannot be accurately described using the Blake-Kozeny-Carman equation, even though the flow is Newtonian at very low Reynold's number. For aligned fiber situations, the Kozeny constant, k, deviates radically from theory, depends on bed nonuniformities, and is only constant over very narrow porosity ranges. Thus, one cannot experimentally determine k at high porosities and use this value to describe low porosity situations. Theoretical attempts, based on perfectly spaced and aligned arrays of cylinders, adequately describe the transverse permeability of ideal fiber beds in the high porosity range, but do not succeed at porosities below 0.6. For axial flow through aligned fiber beds, the theory yields permeabilities much lower than are experimentally observed throughout the entire porosity range. For randomly arranged fibers, random cylinder theory also predicts permeabilities that are significantly lower than are measured.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320402
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  • 15
    Electronic Resource
    Electronic Resource
    Stereological measurement and error estimates for three-dimensional fiber orientation (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 240-253 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A method is presented for measuring three-dimensional fiber orientation in fiber-reinforced polymers and placing confidence limits on the results. The orientations of individual fibers are determined from the elliptical intersections between the cylindrical fibers and a polished section. This can be done using either manual digitization or automated image analysis. Volume averages for the sample are computed using an orientation-dependent weighting function that corrects for the bias of an area-based sample. Equations are developed for nonuniform fiber lengths, using both number-average and weight-average measures of orientation. Sources of systematic, measurement, and sampling error are discussed and equations for sampling error and the propagation of measurement error are derived. The results use a second-rank tensor to characterize fiber orientation, but the error analysis can be applied to any type of orientation parameter. We implement the technique using manual digitization of optical micrographs. Our implementation accurately measures samples with known orientation, and produces identical results from two perpendicular sections of a glass fiber/nylon injection-molded sample.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320404
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  • 16
    Electronic Resource
    Electronic Resource
    Impact resistance performances of polyamide 6 blended with different rubber phases (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 273-279 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: We have studied the impact strength, by Charpy and Izod tests, of blends of polyamide 6 with different rubbers, 10 wt% of each, or rubbers and glass fibers (8.5 wt% and 15 wt% respectively). The rubbers are from three different families: (i) a nonreactive cross-linked terpolymer, methyl methacrylate/butadiene/styrene (17/64.5/18.5); (ii) two block copolymers compatible with the matrix, poly(tetramethylene glycol)/polamide 12 (70/30 or 34/66); and (iii) two polymers containing reactive functionality, a terpolymer ethylene/ethyl acrylate/maleic anhydride (68/30.5/1.5) and a copolymer ethylene/acrylic acid (90/10). The classification of additives in regard to improved impact depends on the procedure used for the impact strength measurement, particularly on whether the samples are notched or unnotched. The results are discussed in relation to the dimensions and the adhesion of the rubber particles. The level of adhesion has been estimated from observations in scanning electron microscopy of cavities due to pullout nodules and of nonextracted rubber after treatment in boiling xylene. Strong variations in the morphologies are found, depending on the chemical nature of the rubber. The crystalline state of the polyamide in the blends has also been evaluated from differential scanning calorimetry.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320407
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  • 17
    Electronic Resource
    Electronic Resource
    The impact performance of thermoplastic sheet composites (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 287-297 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Sheet composites of polypropylene and poly(ethylene terephthalate) were produced by melt consolidation of alternating layers of polymer films and random glass fiber mats. The composites had a nominal glass content of 50 wt% (∼30 vol%). The sheets were stamped into a complex part from which test specimens were machined, and mechanical properties determined. Flexural strengths as high as 159 MPa were recorded for polypropylene composites and 313 MPa for poly(ethylene terephthalate) composites. The flexural modulus of the polypropylene composites reached 9.1 MPa, whereas the modulus of the stiffest poly(ethylene terephthalate) composite was 15 GPa. The impact properties of the composites were equally high. Polypropylene composites absorbed up to 257 J/cm during an instrumented falling dart impact test. Poly(ethylene terephthalate) composites absorbed as much as 116 J/cm in the same test.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320409
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  • 18
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320501
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  • 19
    Electronic Resource
    Electronic Resource
    Interpretation of fiber fragmentation in carbon/epoxy single fiber composites: Possible fiber pre-tension effects (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 298-304 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The fiber straightening pre-tension applied during the sample preparation of single fiber composites is suggested here to significantly affect the number of fragments as well as the value of the Kelly-Tyson interface shear strength obtained from single filament composite tests. This implies that fragmentation tests performed under seemingly identical conditions, but in which the fiber pre-tension is not accurately controlled during sample preparation, might yield widely differing experimental results. We present and discuss a new set of experimental results dealing with fiber pre-tension effects in carbon/epoxy single fiber composites.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320410
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  • 20
    Electronic Resource
    Electronic Resource
    The effects of transcrystalline interphase in advanced polymer compositesThis paper has been presented in part or in full at the Materials Research Society Symposium N, Boston, November 1989; the Third International Conference on Composite Interfaces, Cleveland, May 1990; and the Textile Institute World Conference, Dundee, Scotland, November 1990. (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 280-286 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Surface-induced transcrystallization in fibers has been reported in some advanced polymer composites. It is believed that transcrystalline interphase may affect stress transfer efficiency between the reinforcing fiber and the matrix. In this study, attempts were made to examine the effects of transcrystallinity on composite performance, particularly on fiber-matrix interfacial bond strength, and to investigate possible attributes of transcrystallization. Three polymer resins, poly(etherketoneketone) (PEKK), poly(etheretherketone) (PEEK), and poly(phenylenesulfide) (PPS), and four types of fiber, polyacrylonitrile (PAN)-based AU-4 (untreated AS-4) carbon, pitch-based carbon, poly (p-phenylene terephthalamide) (PPDT) aramid, and E-glass were used. It was found that PPDT aramid and pitch-based carbon fibers induce a transcrystalline interphase in all three polymers because of an epitaxial effect. Under certain conditions, transcrystallization was also observed in PAN-based carbon and E-glass fibers, which may be partially attributed to the thermal conductivity mismatch between the fiber and the matrix. Plasma treatment on fiber surface showed a negligible effect on inducing transcrystallization, whereas solution-coating of PPDT on the fiber surface showed a positive effect. The Microdebonding test, which measures the interfacial bond strength between the fiber and the matrix, consistently showed more than 40% increments for various single filament systems with transcrystalline interphase versus without. However, the effects of transcrystallinity on the interfacial bond strength appeared to decrease as the fiber content increased in composites.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320408
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  • 21
    Electronic Resource
    Electronic Resource
    Optimization of stabilizer formulations for polyolefin processing (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 475-480 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An approach to formulation is presented that is based on a statistical experimental design package for use on a personal computer. The total level of phosphite + hindered phenol, and the ratio of phosphite to hindered phenol are used as experimental variables. The approach was tested on extrusions of polypropylene using melt flow retention and yellowness index as observed variables. A quadratic model gave a satisfactory fit to the data for both variables. Contour plots are presented of the performance of the systems for two commercially available hindered phenols and two polypropylene samples. The largest difference between the resins is in the degree of color generation on extrusion. For both hindered phenols, a resin made using “3rd generation” or “high activity” catalyst gave lowest color development on extrusion. There were also small differences in the response of the melt flow of the resins to phosphite level.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320704
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  • 22
    Electronic Resource
    Electronic Resource
    Structure and physical properties of biaxially stretched polyethylene terephthalate sheet after heat-setting (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 481-487 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The consumption of hot-fillable poly(ethylene terephthalate) bottles is extremely large and is still increasing in Japan. This type of bottle is generally manufactured by the heat-set method using hot molds after stretch-blow molding. In this study, the method is simulated using a setting application in which sheets can be stretched constraining their sizes on a hot aluminum block. The crystallinities of the sheets are found to depend on the thermal history, i.e., the duration and temperature of the heat-set cycle. Heat-setting mitigates thermal-shrinkage of the sheets which is due to the increase in crystallinity or in the tense segments in the amorphous region. The structure of the heat-set sheet varies depending on the original stretched sheet. For a sample of low draw ratio, the crystallinity does not increase because of the heat-set. For a sample of medium draw ratio, the crystallinity increases greatly and the tense segments in the amorphous region also increase because of heat-set. For a sample of high draw ratio, the crystallinity increases a little but the numbers of the crystallite and tense segments in the amorphous region do not change with the heat-set.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320705
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  • 23
    Electronic Resource
    Electronic Resource
    Dynamics of a continuous stirred tank reactor for styrene polymerization initiated by a binary initiator mixture. II: Effect of viscosity dependent heat transfer coefficient (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 494-505 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dynamic behavior of the solution polymerization of styrene in a continuous stirred tank reactor is analyzed with a mixture of tert-butyl perbenzoate and benzoyl peroxide as an initiator system. In the modeling of the reactor, a viscosity dependent reactor wall heat transfer coefficient is used to account for the changing heat transfer efficiency as monomer conversion and polymer molecular weight increase. The steady state and bifurcation behaviors have been investigated with the reactor residence time, initiator feed composition, initiator concentration, feed solvent volume fraction, and coolant temperature as bifurcation parameters. Unlike the reactors with constant heat transfer coefficient, the present system exhibits relatively simple steady state and dynamic bifurcation behaviors. Oscillatory behavior is observed only when the solvent volume fraction in the feed exceeds 0.2. The dynamic simulation of the reactor also indicates that a feedback temperature controller may fail to maintain the reactor temperature when the heat transfer coefficient changes as a result of process disturbances.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320707
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  • 24
    Electronic Resource
    Electronic Resource
    Analysis of the deformation of polypropylene hot-tool butt welds (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 586-592 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Thin microtomed samples from hot-tool butt welds of polypropylene pipes are subjected to uniaxial tensile stress using a specially built instrumented microtesting machine. The deformation of the interface between the weld and the bulk polymer is measured by an optical method. An analysis of these measurements is carried out using the finite element method, and contours of the effective stress are obtained. There is a steep stress gradient at the junction of the weld flash and the bulk polymer, although the stress concentration factor is relatively low. The stress is essentially constant in the bulk polymer apart from the region near the weld zone. Tests on samples without the weld flash show that the maximum stress occurs within the weld zone. This is consistent with long-term tests on larger samples, where the fracture is found to initiate within the weld. The method of analysis enables the stress-strain response of the weld material to be determined.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320904
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  • 25
    Electronic Resource
    Electronic Resource
    Ultrasonic welding using tie-layer materials. part I: Analysis of process operation (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 600-611 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Ultrasonic welding of oriented polypropylene (OPP) using tie-layer materials has been examined. The thermal cycle at the joint interface was evaluated using a high speed data acquisition system, and concurrent changes in horn displacement (penetration) and the output power were monitored. The model explaining process operation involves four phases, i.e., I-where heating occurs because of the stresses generated in asperities on the contacting surfaces; II-where the whole tie-layer reaches the melting point; III-where the polymer melt is subjected to intense heating from viscous dissipation and is squeezed out; and IV-where the joint cools after welding. In the early stages of ultrasonic welding the heat generated at asperities on the contacting surfaces leads to melting of the tie-layer/oriented polypropylene interface within 50 ms. The tie-layer heats up because of a combination of viscoelastic dissipation and heat conduction from the oriented polypropylene/tie-layer interface, and the rate of temperature rise at the midline of the tie-layer is in the range 200°/s to 400°/s. The reduction in thickness of the test specimens (penetration) is negligible up to the time when the tie-layer melts completely, and then changes rapidly when the melted polymer at the joint interface is squeezed out. The influence of machine parameters (amplitude and contact pressure) and of tie-layer Melt Flow Index is also examined. The total time required for completion of the welding process decreases when the amplitude and applied pressure are increased. The use of low Melt Flow Index tie-layers produces peak temperature as high as 600° at the bondline, and little material is ejected during the ultrasonic welding operation.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320906
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  • 26
    Electronic Resource
    Electronic Resource
    On the solution of fiber orientation in two-dimensional homogeneous flows (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 810-822 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This work presents an analytical technique to describe the orientation behavior of short fibers in arbitrary two-dimensional homogeneous flows. It is shown that the fiber orientation, specified by a unit vector, can be analytically calculated at any instant using any initial orientation and flow kinematics. The rotation of a fiber with the bulk fluid deformation is expressed in terms of orientation vector components by utilizing an equivalent strain tensor calculated from the fluid kinematics. This technique is then used to evaluate the orientation behavior of a large number of fibers starting from different initial orientations, representing an orientation state. The orientation distribution function is generated statistically by considering the frequency distribution curve of the orientation of the large number of fibers. It is shown that using a combination of analytical solutions and statistical methods provides a convenient description of fiber orientation behavior. The accuracy of the generated orientation distribution function is found to be dependent on the number of fibers used in the analytical solution. The statistical orientation distribution function is compared with the exact solutions for certain homogeneous flows and found to be in close agreement.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321208
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  • 27
    Electronic Resource
    Electronic Resource
    Cure of epoxy resins containing epoxidized polyols (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 836-840 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A commercial epoxy resin, consisting of a mixture of diepoxides based on diglycidyl ether of bisphenol-A (DGEBA) and containing an epoxidized polypropylene glycol as reactive diluent, was characterized by 1HNMR, FTIR, SEC, and chemical analysis. The kinetics of the cure with ethylenediamine (EDA) was catalyzed by the (OH) groups present in a large amount in the commercial formulation. A second order kinetic behavior gave an accurate fitting of results obtained by different experimental techniques (DSC in dynamic and isothermal modes and SEC in the pregel stage). The activation energy was E = 59.1 kJ/mol (14.1 kcal/mol), in very close agreement with values reported for the catalytic mechanism of the DGEBA-EDA polymerization. From the gel conversion and the critical stoichiometric ratio for samples containing an epoxy excess it was found that the average functionality of epoxidized species was f = 1.58.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321211
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  • 28
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    Electronic Resource
    Percolation in injection molded polymer blends (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 841-844 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Elastic moduli of injection molded blends of polycarbonate with poly(styrene-co-acrylonitrile) (SAN) have been obtained at temperatures between the glass transition temperatures of the two components. When compared with compression molded blends as a function of composition, the moduli were found to differ by as much as a factor of three at intermediate compositions. The variations are ascribed to differences in connectivity between minor component particles. The morphologies of these materials have been modeled using percolation concepts to quantify continuity of the individual phases. The effects of phase continuity resulting from composition as well as dispersed phase shape differences were evaluated. It was found that shape per se has only a minor effect on percolation. However, shape as reflected in the size of dispersed particles relative to the extent of the domain in which they reside is primary for developing a model for continuity of the phases. An empirical relation for percolation in finite domains was devised from Monte Carlo simulations. Modulus values calculated from these continuity considerations agree well with the observed data.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321302
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  • 29
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    Characterization of thermotropic liquid crystalline polyester/polysulfone blends (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 854-860 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The morphology, rheology, and mechanical properties of blends of polysulfone (PSF) with up to 65% of a wholly aromatic liquid crystalline polymer (LCP) were investigated. In injection molded specimens a skin-core morphology was observed with the LCP minor phase oriented in the skin and globular in the core. Scanning electron microscopy of fractured surfaces showed sharp phase boundaries, suggesting low interfacial adhesion. The neat PSF and blends with low amounts of LCP exhibited a low shear Newtonian plateau not observed in the blends with high LCP levels. The addition of LCP to PSF resulted in an increase in stiffness, a small increase in tensile strength, and a significant improvement in processability.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321304
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  • 30
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    Influence of reprocessing on the mechanical properties of a commercial polysulfone/polycarbonate blend (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 861-867 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Commercial polysulfone/polycarbonate (PSU/PC) polymer blends were reprocessed up to five times to determine the influence that reprocessing has on their structure and physical properties. All the high strain properties, mainly ductility, significantly decreased under harsh processing conditions, such as five cycles at 320°C. The results of reprocessing the blends at 320°C have been compared with results at a lower temperature and also with those of the separate components with the aim of clarifying the origin of the degradation. These results plus Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis, and melt flow index measurements (MFI) indicate that the presence of the two polymers together clearly decreases the resistance to degradation of each component. Moreover, degradation under the stated conditions is mainly thermal and does not change the chemical nature of the blends. However, a clear decrease in molecular weight was observed both by viscosimetry and MFI measurements as was a shift to higher temperatures of the low temperature secondary transition of both PC and PSU. Both molecular weight and secondary transition changes usually deteriorate mechanical properties but not in the degree observed here. This probably means that the fine and difficult-to-observe structure of the blend has also changed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321305
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  • 31
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    Blends of polycarbonate with poly(methyl methacrylate): Miscibility, phase continuity, and interfacial adhesion (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 886-893 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) concurrently show that polycarbonate (PC)/poly(methyl methacrylate) (PMMA) blends have a two-phase structure. The differences between the Tgs of parent polymers and the Tgs of conjugate phases, determined by both DMTA and DSC, indicate a limited miscibility of components and allow the approximate composition of conjugate phases to be calculated. The Flory-Huggins interaction parameter calculated by using these data assumes values about 0.035 ± 0.010. Phase inversion occurs in an interval close to the 50/50 composition, though the molar masses and melt viscosities of the polymers were rather different. Partial miscibility of components ensures interfacial adhesion capable of sustaining the stress transfer between phases up to fracture. Yield stress of the blends is very close to values foreseen by the rule of mixtures. A specific feature of the blends studied is that the addition of 10 to 20 vol% of PMMA to PC increases the strain at break and work to fracture, which are rather low for the PC used. The enhanced capability of the blends to absorb mechanical energy is probably linked to plastic deformation of the dispersed PMMA.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321308
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  • 32
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    Electronic Resource
    Blends of modified polycarbonate and high density polyethylene (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 894-902 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In this work, blends of polycarbonate and a high density polyethylene were investigated through their morphology, mechanical properties, and the effect of compatibilizers: a copolymer styrene-butadiene-styrene and an ionomer. Blending was performed in the melt state at 220°C, and the concentration of the compatibilizers was varied from 1% to 5% by weight. In the case of the copolymer modified blend, the results showed no change in the mechanical properties compared to the neat blend, whereas the morphology showed that the copolymer might interact with only one phase. For the ionomer, the addition of 1% increased the Young's modulus and the tensile strength of the blend. For the morphology, a large change in the size of the dispersed phase (polyethylene) is observed. This was attributed to the compatibility of the ethylene group of the ionomer with the minor phase, and the reaction between the carbonate group of polycarbonate (PC) and the acid group of the ionomer. An investigation on the binary blends of PC and the ionomer showed the occurrence of a chemical reaction that might be of a transesterification type. Differential scanning calorimetry and Fourier transform infrared techniques were used to characterize these blends.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321309
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  • 33
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    Electronic Resource
    Masthead (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321401
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  • 34
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    Electronic Resource
    Negative synergism of crosslinking agent and antioxidant in polyethylene (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 921-923 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The melt flow index and oxidation induction period of low-density polyethylene crosslinked with dicumyl peroxide (DCP) in the presence of tetrakis (methylene β-3, 5-di-butyl-4-hydroxypheny1)-propionate methane (Antioxidant 1010) were determined. The results suggest that there is a negative synergism between this crosslinking agent and antioxindant. Part of the antioxidant terminated the chain propagation by trapping radicals, and thus reduced the efficiency of crosslinking. The antioxidant efficiency was also reduced owing to meaningless consumption.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321402
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  • 35
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    Fractography of injection molded polycarbonate acrylonitrile-butadiene-styrene terpolymer blends (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 909-919 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Fractography has been used in the post-failure analysis of single edge notched specimens of injection molded blends of polycarbonate (PC) and acrylonitrile-butadiene-styrene terpolymer (ABS). The mode of ductile tensile fracture of single edge notched specimens depended on comosition. Plane stress shear tearing was observed in the composition range PC/ABS 90/10 to 70/30 by weight where PC was the continuous phase. Intermediate compositions, PC/ABS 60/40 to 40/60, had a co-continuous or almot co-continuous phase morphology; these blends fractured by mixed mode pop-in, where a tunneling center crack relieved the triaxiality and permitted plane stress shear lips to form near the edges. Herringbone fracture, a plane strain mode characterized by discontinuous crack growth, was observed when ABS was the continuous phase, PC/ABS 30/70 to 10/90. An S-shaped relationship was observed between the ductile-to-brittle transition temperature and the composition. Addition of ABS to PC increased ductility up to PC/ABS 70/30 and 60/40, which were the most ductile compositions. Further addition of ABS decreased the ductility, and the least ductile compositions were PC/ABS 30/70 and 10/90.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321311
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  • 36
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    Finite element modeling of the time-dependent behavior of nonlinear ductile polymers (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1086-1096 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A finite element algorithm developed previously has been successfully extended to the study of nonlinear time-dependent problems. Nonlinear viscoelastic and viscoplastic models have been used to study the time-dependent deformation and failure of high density polyethylene (HDPE). Two classes of nonlinear models have been identified; those that allow stress redistribution with time under specified traction boundary conditions, and those that do not. The implications of using viscoelastic vs. viscoplastic models, as well as the specific mathematical form of the constitutive equations selected for use, have been studied. Strains predicted using the FE algorithm have been compared with experimental measurements for (i) a HDPE plate with a hole and (ii) a double edge notch HDPE specimen, both under remote tension. Excellent agreement was obtained between numerical predictions and the experimental values.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321606
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  • 37
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    Influence of thickness and processing history on fatigue fracture of nylon 66. Part I: Crack propagation measurements (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1105-1113 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The influence of sample thickness on fatigue crack propagation rates in injection molded nylon 66 was determined by preparing 12.7 mm thick plaques along with more conventional 3.0 mm thick samples. Initial results suggested a large effect of thickness as the crack propagation rates were accelerated in the thicker samples and the stress dependence was also increased. Since the calculated thickness for a plane stress to plane strain transition in nylon 66 is 9.0 mm, it was thought that these results were related to the stress state at the crack tip. However, a more thorough study of the thicker plaques has now demonstrated that neither the magnitude nor the stress dependence of the fatigue crack growth rates is necessarily changed under plane strain conditions as similar results can be obtained for thick and thin plaques. It is suggested that the earlier results were confounded by a previously unrecognized processing history effect which does accelerate fatigue fracture. The latter effect is shown by thermal analysis and optical microscopy to be related to a rearrangement of the polymer network during melt processing.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321608
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  • 38
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    Influence of thickness and processing history on fatigue fracture of nylon 66. Part II: Crack tip morphology (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1114-1125 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Fatigue crack propagation rates in injection molded nylon 66 were previously shown to be strongly affected by prior processing history. To provide a physical basis for the observed acceleration in crack growth rates, microtomed sections were cut through the tips of stable fatigue cracks and examined by optical microscopy. A reduction in spherulite size occurs with reprocessing along with an accompanying decrease in the amount of deformation at the crack tip. For the initially processed nylon 66 this deformation consists of a vast array of independently initiated craze-like zones. Patchy type regions observed on the fatigue fracture surface are similar in size to the initially formed crazed zones. Crack advance occurs by the breakdown and coalescence of the crazed regions via matrix shearing. The extensive damage zone is believed to result in a reduction in stress intensity at the crack tip thereby reducing the crack propagation rates. For the reprocessed nylon 66, one observes fewer crazes and a sharper fatigue crack tip with a consequent acceleration in crack propagation rates and a smoother fracture surface.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321609
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  • 39
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    An investigation of brittle failure in ductile, notch-sensitive thermoplastics (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1126-1137 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Brittle failure, a significant design issue for plastic components subject to impact loads, is especially catastrophic when the material is normally ductile. Such behavior is not adequately understood relative to the micromechanisms, controlling parameters, and design consequences in plastics. Previous work has identified the process of crazing as being relevant to these failures in thermoplastics. The relationship between crazes generated through mechanical loading and subsequent brittle failure of amorphous thermoplastics is discussed and the hypothesis that the craze event is a necessary but insufficient condition for brittle failure is employed. Emphasis is focused upon the engineering prediction of craze formation and its use as a conservative brittle failure criteria for defining geometric details to prevent brittle failure. First, a series of experiments using one geometry is applied to study the concept of crazing as a precursor to brittle fracture in the two amorphous polymers polycarbonate and polyetherimide. Second, three-dimensional finite element analyses are used to assess the effects of changes in geometric detail upon the continuum stress state and eventual failure of the specimen for these two materials.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321610
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  • 40
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    Constitutive modeling and simulation of energy absorbing polyurethane foam under impact loading (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1138-1146 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The compressive-stress strain response of polyurethane foam under uniaxial compressive impact loading has been studied. The development of a uniaxial constitutive model from strain rate controlled compression tests is detailed. Density and temperature functions have been added to the integral power model proposed by Schwaber, Meincke, and Nagy. The model assumes that the effects of density, temperature, strain and strain rate on stress are separable functions. The model correlated well with actual static compression tests and was used successfully to predict the impact response of energy absorbing polyurethane foam under uniaxial compressive loading.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321611
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  • 41
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    Masthead (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321701
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  • 42
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    Dr. Bernhard Wunderlich: An innovative educator pioneer in the physical chemistry of polymers (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1177-1187 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321702
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  • 43
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    Electronic Resource
    Experimental and numerical investigations of the vacuum-forming process (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1163-1173 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This paper exmines the influence of process variables on final thickness distributions for vacuum-formed thermoplastic parts. The process variables investigated include evacuation rate, sheet surface temperature, mold temperature, and material slip over the mold surface. The experimental data presented include, in addition to thicknesses, sheet surface temperature obtained via infrared thermography. A finite element program to model the vacuum-forming process is discussed, and the wall thickness distribution predicted by this program for a vacuum-formed part is compared with the results of the experiments.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321613
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  • 44
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    The effect of cyclic stress on the physical properties of a poly(dimethylsiloxane) elastomer (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1350-1357 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dynamic creep behavior of a filled poly(dimethylsiloxane) elastomer was studied under cyclic stress. The stress level was chosen such that the increase in the internal temperature was small and that microcracks were not observed. This work has demonstrated that cyclic stress in combination with high temperature accelerates the degradation of the elastomer. The results suggest that because of the applied force, breaks in the load-bearing chains of the network occur. These breaks, while relieving the mechanical stress, create highly reactive ionic fragments. It is believed that because of the subsequent reactions of the ionic fragments, changes in the specific gravity, storage modulus, effective crosslink density, and length of the sample (creep) are observed. The observed decrease in the storage modulus is thought to occur because of the reaction of the ionic fragments with moisture, which results in the formation of silanol chain ends that reduce the effective crosslink density. The results also show that contrary to the prediction of the Boltzmann's Superposition Principle, the rate of creep is greatly enhanced when the sample is subjected to a sinusoidally varying dynamic load as compared to a comparable static load. The polymer weight loss was found to be linear with time and strongly dependent on the level of applied dynamic and static force. In addition, the weight loss and rate of creep were also found to be strongly dependent upon temperature.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321803
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  • 45
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    Optical characterization of three-dimensional surface and bulk anisotropy in high refractive index polymers (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1358-1365 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Interest in the development of polymeric materials for high temperature, electronic and microelectronic applications has led to an increasing number of new polymers. Many of these polymers have complex organic ring structures and semirigid backbones, characteristics that have posed some difficulties for structural analysis. The purpose of this paper is to test and compare two practical nondestructive optical techniques, polarized optical microscopy and polarized refractometry, for the determination of three-dimensional surface and bulk anisotropy in these advanced materials. The optical techniques are first tested on a series of optically homogeneous uniaxially oriented isotactic polypropylene films and then applied to the analysis of high refractive index Kapton (PMDA-ODA) polyimide films. The study includes a test of the validity of the compensator method, including the effect of fringe jumping, the use of polymer retarders, and the tilting technique of Stein.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321804
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  • 46
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    Electronic Resource
    Effectiveness of polymer coatings on reducing indention damage in glass (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1372-1378 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polymer coatings are widely used to protect glass from indentation damage. A model for the strength degradation that occurs when a sharp indenter penetrates through the coating is developed by accounting for the indentation load shared by the coating and substrate. This model accounts for the additional load supported by the coating due to the pile-up of coating material underneath the indenter. The model predicts the strength degradation as a function of indentation load, coating and substrate hardnesses, and coating thickness. Comparison of the model to experimental data for a wide range of polymer coatings (two epoxies, epoxy acrylate, and urethane acrylate) on soda-lime glass substrates shows good agreement.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321806
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  • 47
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    Novolak resins with high thermal stability, high resolution, improved photospeed and etch characteristics for advanced photoresist applications (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1500-1508 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Novolak resins provide the best overall performance for “g” and “i”-line photoresists. There is a continuing need for advanced novolak designs that will provide improved lithographic, thermal, and etch characteristics that may be reproducibly synthesized. A novolak synthesis process was developed using the solution condensation technique. Cresol mixtures with m-cresol and 3,5-xylenol at specific ratios provide reproducible novolaks with controlled molecular weights. In order to achieve high thermal and etch performance, while retaining photospeed and resolution characteristics, three basic approaches were investigated: (1) increase in molecular weight, which produces novolaks with Tg ranging from 120 to 130°C with relatively slow dissolution rates; (2) incorporation of multi-hydroxyphenols such as resorcinol to tailor the dissolution rate, resolution, thermal, etch, and adhesion characteristics; (3) partial esterification of multi-hydroxy novolaks giving a Tg range of 140 to 150°C. Lithographic evaluation of the novolak resins was performed by formulating with a 2,1,4-diazonaphthoquinone (DNQ) sensitizer. Results on resin synthesis, molecular weights, lithographic, thermal, and etch characteristics are discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760322010
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  • 48
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    Acid formation from various sulfonates in a chemical amplification positive resist (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1511-1515 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The quantum yield for acid generation from alkyl and arylsulfonic acid esters of pyrogallol was measured in resist films composed of a sulfonate, tBOC-BA, and novolak resin. It was found that the quantum yield increases with decreasing molecular size of the sulfonyl group, which can explain the differences in sensitivity of the resist systems. Methanesulfonic acid esters of various phenol derivatives were synthesized to see the effect of backbone structure on the efficiency of acid generation. The sensitivity measurement of resists containing these sulfonates indicates that the number of sulfonyloxy groups bonded to a benzene ring is important. The higher number of the sulfonyloxy groups gives a higher efficiency of acid generation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760322012
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  • 49
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    t-BOC blocked hydroxyphenyl-methacrylates: On the way to quarter micron deep-UV lithography (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1516-1522 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: t-Butyloxycarbonyl (t-BOC) blocked compounds based on the protection of phenolic groups, e.g. poly-4-hydroxystyrene derivatives, Bisphenol A type dissolution inhibitors, or onium salt photoacid generators, have found widespread research interest for photoresist systems with excellent photosensitivity and high resolution power. We have made an extension of this approach using new phenol type polymers. This contribution presents first details on the chemistry of these systems and results of their lithographic evaluation as positive tone photoresists for deep UV applications.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760322013
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  • 50
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760322101
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  • 51
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    Preamble (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1557-1557 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760322102
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  • 52
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    ARCOR, a new photolithography technique with antireflective coating on resist (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1545-1549 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The multiple interference effect is one of the major causes of the fluctuation in critical dimension control (CD) and in mark detection for alignment. Suppressing this effect is critical for future photolithography. We propose a new photolithography technique called anti reflective coating on resist (ARCOR), which improves linewidth accuracy and overlay accuracy by suppressing multiple interference. ARCOR consists of relatively simple processes: A clear antireflective film is spun onto the resist prior to the mark detecting for alignment and exposure. The film is subsequently removed and the resist developed in the conventional way. ARCOR differs from ARC, which suppresses the reflection at the resist/substrate interface. ARCOR suppresses the reflection at the air/resist interface. ARCOR allows mark detection and exposure without light intensity-loss and multiple interference. The experiments mainly examine polysiloxane and perfluoroalkylpolyether as ARCOR materials. It is shown that linewidth accuracy can be improved from 0.3 to 0.03 μm. The signal-to-noise ratio of the alignment signal is drastically improved, and the overlay error is about half that of the conventional method. ARCOR is also effective for directly measuring the reflectivity at the resist/substrate interface, which is a key parameter of the multiple interference effect and the halation. Using ARCOR and a thin resist film, the measured ratio of reflected light to incident light indicates the reflectivity at the resist/substrate interface. Because, the probe light does not reflect off the resist surface and the intensity-loss at the resist surface is suppressed. With perfluoroalkylpolyether film, the measurement error is ∼ 1.5%.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760322018
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  • 53
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    Determination of Nifedipine in plasma by a rapid capillary gas chromatographic method (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 20-23 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A rapid, specific and reliable gas chromatographic assay procedure for Nifedipine in plasma has been developed. With a single-step solvent extraction, and electron capture detection, the method is sensitive to 0.5 ng/mL of plasma and the standard curve is linear from 0.5 to 500 ng/mL. Samples are protected from light to prevent formation of photodecomposition products. The method has been used to monitor drug concentrations in patients receiving therapeutic doses.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060107
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  • 54
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    Favourable biospecific reactivity of blood group B antigenic trisaccharide chemically attached to poly-N-(2-hydroxyethyl)acrylamide-coated porous glass (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 39-42 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Blood group B antigenic trisaccharide-β-aminopropyl glycoside (B-TSAP) covalently attached to poly-N-(2-hydroxyethyl)acrylamide-coated porous glass interacts with anti-B monoclonal antibodies faster than the ligand coupled to CNBr-activated Sepharose 4B and Affi-Gel 10. Rates of hydrophobic adsorption of antibodies on the butyl derivatives of the same supports were measured to evaluate the diffusion input to overall kinetics. The lowest average affinity adsorption time [t1(aff) = 250 s] observed for polymer-coated glass probably arises because of the flexibility of the extended segments of chemisorbed N-substituted polyacrylamide acting as effective spacer arms.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060111
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  • 55
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    Combined application of analytical high performance thin layer chromatography and electroblotting for the detection of anti-ganglioside antibodies in human sera (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 67-71 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Antibodies against gangliosides isolated from small tumour and nervous tissue specimens can be reliably detected in serum samples by the ganglioside electrotransfer technique without the need for previous purification steps. After separation by high performance thin layer chromatography gangliosides are transferred from silica gel plates to hydrophobic polyvinylidene difluoride membranes. These membranes are highly suitable for immuno-staining. The use of a 15-slit device allows simulataneous testing of up to 15 serum samples. Samples of serum from 39 patients with clear-cell carcinoma of the kidney, mammary carcinoma, ovarian carcinoma and neurological disorder together with samples from healthy controls were tested for anti-ganglioside antibodies from various tissues.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060205
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  • 56
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    High performance liquid chromatographic determination of 1,5-anhydroglucitol in human plasma for diagnosis of diabetes mellitus (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 63-66 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This paper describes a high performance liquid chromatographic (HPLC) method for determining 1,5-anhydroglucitol in plasma, in which anion exchange chromatography and pulsed amperometric detection are used. Plasma samples deproteinized with trichloroacetic acid are passed through a three-layer column packed with (1) strongly basic anion (BO3-3 form, the upper layer), (2) strongly basic anion (OH- form, the middle layer) and (3) strongly acidic cation (H+ form, the lower layer) exchange resins. 1,5-Anhydroglucitol is efficiently recovered in the flow-through fraction and interfering substances are completely removed by the column treatment. The analytical response of the method is linear with concentration to 40 mg/L, and it is possible to detect as little as 0.1 mg 1,5-anhydroglucitol per litre of plasma. Analytical recovery is between 96 and 103%, and there is good agreement between the results measured by our method and by a gas/liquid chromatographic method (r = 0.998). The method has been successfully used for the determination of very low 1,5-anhydroglucitol concentrations (〈 1 mg/L) in the plasma of diabetic patients.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060204
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  • 57
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    Peroxyoxalate chemiluminescence detection of condensates of malondialdehyde with thiobarbituric acids using a flow system (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 55-58 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The peroxyoxalate chemiluminescence(CL) detection method for the evaluation of the CL intensity of malondialdehyde(MDA) condensates with seven 2-thiobarbituric acid derivatives is described. The method consists of a flow injection technique together with a CL detection system using bis(2,4,6-trichlorophenyl) oxalate(TCPO) and hydrogen peroxide as chemiluminogenic reagents. Linear correlations between CL intensity and concentration are obtained for pmol levels of condensates. Among the condensates, 1,3-diethyl-2-thiobarbituric acid(DETBA)-MDA shows the largest CL intensity. High performance liquid chromatography (HPLC)/CL detection of DETBA-MDA and 1,3-diphenyl-2-thiobarbituric acid(DPTBA)-MDA using a mixture of TCPO and hydrogen peroxide in acetonitrile as a postcolumn reagent solution is also described. The detection limits for DETBA-MDA and DPTBA-MDA are 20 and 200 fmol, respectively, per 20 μL injection at a signal-to-noise ratio of 2. This HPLC/CL detection system was applied to the defermination of MDA in rat brains by using DETBA as a fluorescent derivatizing reagent.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060202
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  • 58
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    Phosphotungstate as a useful eluent for hepatitis-B virus surface antigen purification by heparin-sepharose affinity chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 72-76 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: On the basis of the heparin-like effect of phosphotungstate (PTA), we have shown that it is useful for the purification of hepatitis-B virus surface antigen (HBsAg) using heparin-Sepharose affinity chromatography. HBsAg was eluted with 0.2-0.6 M NaCl. HBsAg was also eluted with PTA at approximately 1 mM, and the HBsAg fraction thus obtained contained fewer impurities than the corresponding fraction eluted with NaCl. Moreover, PTA yielded HBsAg and hepatitis-B virus e-antigen simultaneously. PTA may specifically reduce the affinity of HBsAg for heparin as well as simply competing with heparin for an anion-binding site of HBsAg. Residual PTA in the eluate was easily decomposed by alkalization, which was useful for subsequent studies.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060206
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  • 59
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    Simultaneous determination of paraquat and diquat in serum using capillary electrophoresis (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 91-94 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The use of capillary electrophoresis for simultaneous separation and detection of the two bipyridylium herbicides, paraquat and diquat, was investigated. Both herbicides were extracted from fortified sera with disposable ODS-silica cartridges. Separation was carried out using a capillary tube (50 μm i.d., 750 mm) of fused silica containing 10 mM glycine-HCl buffer (pH 3.0), 40 mM NaCl and 20% methanol as the carrier. Paraquat and diquat were completely separated in 10 min at an applied potential of 20 kV. On-column UV monitoring allowed detection of both herbicides simultaneously. The assay sensitivity was 0.05 μg/mL (signal-to-noise ratio, 2:1), which probably increases with increase in the sample volume of serum. Analytical recovery of both herbicides added to serum was about 97% at concentrations of 0.5-2.0 μg/mL.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060210
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  • 60
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    Simple and highly sensitive determination of free fatty acids in human serum by high performance liquid chromatography with fluorescence detection (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 120-123 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A highly sensitive and simple reversed phase high performance liquid chromatographic (HPLC) method for the quantitative determination of free fatty acids in human serum is presented. The method is based on the direct derivatization of serum fatty acids with 6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone-3-propionylcarboxylic acid hydrazide. The derivatization reaction proceeds in aqueous solution in the presence of pyridine and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at 37°C. The resulting derivatives are separated within 75 min on a reversed phase column (YMC Pack C8) with a gradient elution of aqueous acetonitrile and detected fluorimetrically. The detection limits are 2.5-5 fmol in a 10 μL injection volume. The sensitivity permits precise determination of free fatty acids in 5 μL serum. The method is simple and is without the conventional liquid-liquid extraction steps of serum fatty acids.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060304
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  • 61
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    Measurement of N-acetylneuraminic acid in human serum and urine by high performance liquid chromatography with chemiluminescence detection (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 135-140 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A highly sensitive method for the determination of N-acetylneuraminic acid in human serum and urine is investigated. This method employs high performance liquid chromatography with chemiluminescence detection. N-Acetylneuraminic acid, released by hydrochloric acid hydrolysis of serum and urine, and N-glycolylneuraminic acid (internal standard) are converted into chemiluminescent derivatives with 4,5-diaminophthalhydrazide dihydrochloride, a chemiluminescence derivatization reagent for α-keto acids. The derivatives are separated within 35 min on a reversed phase column, TSKgel ODS-120T, with isocratic elution, followed by chemiluminescence detection; the chemiluminescence is produced by the reaction of the derivatives with hydrogen peroxide in the presence of potassium hexacyanoferrate(III) in alkaline solution. The detection limit for N-acetylneuraminic acid is 9 fmol (signal-to-noise ratio = 3). This sensitivity permits precise determination of N-acetylneuraminic acid in 10 nL of serum or 50 nL of urine. The method is applied to the determination of the N-acetylneuraminic acid in human sera from normal subjects and cancer patients and in normal urine.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060308
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  • 62
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    Dissolution assay of theophylline, diprophylline and proxyphylline from a sustained release dosage form by high performance thin layer chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 141-142 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The content and dissolution rate of theophylline, diprophylline and proxyphylline from a sustained release formulation were determined by UV in situ densitometry. After separation the chromatographic zones corresponding to the spots of theophylline, diprophylline and proxyphylline on the high performance thin layer chromatographic plates were scanned in reflectance/absorbance mode at 275 nm. Quantification was performed with a second degree polynomial function over the range 40-200 ng for theophylline and 60-300 ng for diprophylline and proxyphylline. Percentages of dissolved theophylline, diprophylline and proxyphylline were monitored over 1, 3 and 6 h. The method was found to be simple, accurate, reliable, time-saving (up to 18 samples can be determined simultaneously) and low-cost.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/bmc.1130060309
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    An improved method for preparation of perbenzoylated ganglioside-derived sialic acids and nanogram detection of N-acetyl- and N-glycolylneuraminic acid by high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 155-159 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An improved method for the preparation of perbenzoylated ganglioside-derived sialic acids is described. After mild acid hydrolysis, isolation of sialic acids can be achieved by Folch partition (Method A) or by anion exchange chromatography (Method B). Perbenzoylated sialic acids were freed from benzoylation reagents by a second Folch partition. Total recoveries of both methods were found to be ≥90%, calculated from metabolically labelled gangliosides. Derivatized N-acetylneuraminic and N-glycolylneuraminic acids were separated and quantified by isocratic high performance liquid chromatography using a RP18 column as the stationary phase and methanol: water (8:2) as the mobile phase. Both sialic acids were completely separated and eluted as single peaks within 15 min, monitored by UV detection. As little as 20 ng of neuraminic acid could be detected, the detector being linear up to 5 μg tested.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060312
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  • 64
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    Use of immobilized metal ions as a negative adsorbent for purification of enzymes: Application to phosphoglycerate mutase from chicken muscle extract and horseradish peroxidase (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 172-176 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Two enzymes, phosphoglycerate mutase and peroxidase, were purified by using an immobilized metal ion adsorbent for the removal of unwanted proteins. The mutase was obtained pure from a single column, whereas the purification of peroxidase required the use of a thiophilic adsorbent in a tandem. The capacity was 2.5 mg pure peroxidase per mL gel.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060404
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  • 65
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    TLC separation of certain tetracycline and amino glycopeptide antibiotics (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 196-197 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The separation of tetracycline and amino glycopeptide antibiotics was achieved on silica gel thin layers. Tetracycline antibiotics were resolved on a Co+2 (1.0%) impregnated silica gel layer using ethanol:acetic acid: water (10:6:6, v/v/v) as the mobile phase. Amino glycopeptide antibiotics were separated on an untreated silica gel layer using the mobile phase n-butanol: formic acid: water (6:5:7, v/v/v). The spots of these antibiotics were located by exposing the chromatoplate to iodine vapours.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060409
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  • 66
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    Isolation of human haemopexin in apo-form by chromatography on S-sepharose fast flow and blue sepharose CL-6B (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 212-214 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060412
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  • 67
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    A simple method for the quantification of famotidine in human plasma and urine by paired-ion high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 222-223 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A new method for the quantification of famotidine consists of a simple extraction procedure and paired-ion high performance liquid chromatography with ultraviolet detection. The method has good accuracy and precision and should be suitable for the routine measurement of plasma and urine samples for clinical studies.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060503
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  • 68
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    Determination of naphazoline in rat plasma using column liquid chromatography with ultraviolet detection (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 241-243 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A sensitive (1 ng/mL) and rapid method for the determination of naphazoline in rat plasma is described. Following extraction, the compound is analysed by reversed phase high performance liquid chromatography and ultraviolet detection at 214 nm.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060508
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  • 69
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    A new method for the purification of cytochrome-P450 from human liver microsomes (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 248-250 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A procedure for the solubilization and purification of cytochrome-P450 (cyt-P450) from human liver microsomes is described. Successive treatment of microsomes with protease XXVII and 3-(3-cholamidopropyl)dimethylammoniopropanesulphonic acid gave a solubilized cyt-P450 in more than 80% yield and with a three-fold increae in specific activity. With this treatment it was possible to eliminate 80% of cytochrome-b5 and 75% of NADPH cyt-P450 reductase. The solubilized cyt-P450 was filtered on a Sephacryl-200 column and then subjected to high performance liquid chromatography with a Mono-P column (chromatofocussing). The recovery of separated cyt-P450 was about 50% with a specific activity of 11.5 nmol cyt-P450/mg protein. Also with this technique it was possible to determinate the isoelectric points of cyt-P450. These results allowed us to confirm the usefulness of our method, for the study the cyt-P450 from surgical biopsies.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bmc.1130060510
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  • 70
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992) 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060201
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  • 71
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    The retention behaviour of conjugated bile acids in reversed phase high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 255-257 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The retention behaviour of conjugated bile acids has been studied in a reversed phase high performance liquid chromatographic (RP-HPLC) system by using the mixture of methanol and aqueous phosphate buffer as the mobile phase. The retentions of the conjugates in RP-HPLC have been found to be mainly controlled by the glycine and taurine groups. The selectivity between five different glycine and taurine conjugated bile acids is a constant in RP-HPLC. This selectivity has been used for peak identification in the practical separation of conjugated bile acids.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060512
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  • 72
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    Editorial (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 263-263 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060603
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  • 73
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    A Selective HPLC/RIA for dexamethasone and its prodrug dexamethasone-21-sulphobenzoate sodium in biological fluids (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 283-286 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A combined high performance liquid chromatography/radioimmunoassay procedure is described for the simultaneous determination of dexamethasone (DEX) and its prodrug dexamethasone-21-sulphobenzoate sodium (DSS) in plasma. After precipitation of the plasma proteins by acetonitrile, the protein-free supernatant was injected onto a C18 reversed phase liquid chromatographic system and DSS- and DEX-containing fractions were collected. Hydrolysis of DSS by 0.01 N NaOH, followed by fractions extraction of both hydrolysed DSS and DEX fractions with ethyl acetate allowed the use of a dexamethasone-specific radioimmunoassay for the selective determination of both compounds. The method is accurate and reproducible (intraday variability for DSS and DEX〈6%, interday variability for DEX 14%), allowing quantification of DEX and DSS as low as 0.3 ng/mL and 0.7 ng/mL, respectively.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060607
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  • 74
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    High performance ion exclusion chromatographic characterization of the vaginal organic acids in women with bacterial vaginosis (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 231-235 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Vaginal organic acids have previously been detected by gas-liquid chromatography, but we have applied an ion exclusion high performance liquid chromatographic procedure to the analysis of vaginal discharge samples. This procedure has the advantage of not requiring derivitization of non-volatile acids and provides the convenience of a technique which does not require the use of flammable gasses, while allowing the identification of at least 18 different acids from the same chromatographic analysis. Vaginal discharge from women with symptoms of bacterial vaginosis was collected on weighed swabs and analysed for the presence of organic acids. The results were compared to the organic acid content of samples obtained from the same cohort of women after treatment with metronidazole. In addition, samples were obtained from asymptomatic women and these samples were analysed in the same manner. The number of organic acids present in samples from women with bacterial vaginosis was greater than the number found after treatment or among asymptomatic women. Succinic acid appeared to be inversely related to lactate concentration and succinate:lactate ratios were greater among women with bacterial vaginosis before treatment than after treatment. Liquid chromatography has proven useful as a means of evaluating the metabolic end-products of vaginal microorganisms in situ.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060506
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  • 75
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    Quantitative determination of CGS 18102A, a new anxiolytic, in human plasma using capillary gas chromatography/mass spectrometry (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 244-247 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: CGS 18102A is a novel hexahydrobenzopyranopyridine that has a mixed pharmacological profile of 5-HT-1A agonist and 5-HT-2 antagonist properties. Based upon these mechanisms, the compound is predicted to have anxiolytic efficacy with possible efficacy in depression. Preclinical studies in the rat have shown the drug to be well absorbed and extensively metabolized. Because of the anticipated low plasma levels in humans a gas chromatography/mass spectrometry (GC/MS) analytical method has been developed and validated to determine plasma concentrations of CGS 18102A in early clinical studies. The method utilizes CGS 18416A as the internal standard. Samples (1 mL) were extracted with pentane:ethyl acetate (75:25, v:v). Extracts were then concentrated and analysed directly by GC/MS. Separation was accomplished on a methylsilicone capillary column (30 m × 0.32 mm i.d.). GC/MS was carried out under positive ion ammonia CI conditions, with selected ion monitoring of the [M + H]+ ions (m/z = 262 and 248) for CGS 18102A and CGS 18416A, respectively. The method was successively applied to the analysis of clinical samples from an ascending multidose safety and tolerability study conducted in six normal healthy male volunteers.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060509
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  • 76
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    Determination of low molecular weight aliphatic primary amines in urine as their benzenesulphonyl derivatives by gas chromatography with flame photometric detection (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 251-254 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A selective and sensitive method for the determination of low molecular weight aliphatic primary amines in urine is described. These amines were converted into their benzenesulphonyl derivatives by a modified Hinsberg procedure, and measured by gas chromatography with flame photometric detection (FPD-GC) using a DB-1 capillary column. The derivatives were very stable and provided excellent FPD responses. By FPD-GC, linear calibration curves were obtained in the range 10-200 ng of methylamine, ethylamine, n-propylamine, isobutylamine and n-butylamine using tert-butylamine as an internal standard, and the detection limits of these amines were ca. 6-25 pg as the injection amount. Benzenesulphonamide derived from ammonia was converted into its N-dimethylaminomethylene derivative which has a longer retention time, and separated from benzenesulphonyl derivatives of low molecular weight primary amines on the chromatogram. The recoveries of aliphatic primary amines added to urine samples were 91-107% and the relative standard deviations were 0.2-4.5%. Analytical results of aliphatic primary amine contents in urine samples of normal subjects are presented.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060511
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  • 77
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992) 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060601
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  • 78
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    Mixed-bed polymeric o-nitrobenzophenone reagents for the on-line derivatization of amines in high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 269-277 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Several polymer-bound o-nitrobenzophenone reagents containing different detector-sensitive tags have been combined in the same reactor for the on-line derivatization of amine samples. The formation of multiple derivatives allows numerous opportunities for quantitation from the same injection, and also allows improved identification from the retention times of the multiple derivatives. Changing the reaction conditions changes the ratio of the products formed, so that changes in the ratio of peak heights and areas can also be used for analyte identification. In this work, propylamine was derivatized in acetonitrile on-line, precolumn. Changing the reaction conditions, of reaction time, temperature, solvent, presence of catalyst and the components of the reactor, changed the ratio of the derivatives formed. These changes in product formation with changing reaction conditions were applied to the identification and quantitation of amphetamine and methamphetamine in urine. The drugs were identified by the retention times of their derivatives, the ratio of te peak areas of the derivatives and the change in the ratios after changing reaction conditions. Each derivative was also used for quantitation of levels of spiked concentrations of amphetamine and methamphetamine, with relative errors less than 8%.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060605
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  • 79
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    A high performance liquid chromatographic method for the determination of albuterol enantiomers in human serum using solid phase extraction and chemical derivatization (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 291-294 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A high performance liquid chromatographic method was developed for the simultaneous assay of R(-)- and S(+)-albuterol in human serum. The assay involves solid phase extraction as a sample clean-up step and derivatization of racemic albuterol to its diastereomeric thioureas with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl isothiocyanate. Chromatographic separation was accomplished under isocratic conditions using an octadecylsilane column and a mobile phase consisting of 29:71 acetonitrile:distilled water containing 0.1% triethylamine, pH 4.0 (adjusted with concentrated phosphoric acid) at a flow rate of 0.8 mL/min. The diastereomers were detected using a fluorescence detector set at 223 nm excitation and no emission filter. Racemic bamethane was used as internal standard. Drug to internal standard peak-height ratios were linear over a 2-20 ng/mL range for each enantiomer. The limit of detection of each analyte was 1.0 ng/mL (S/N = 3).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060609
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  • 80
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    Robotic solid phase extraction and high performance liquid chromatographic analysis of ranitidine in serum or plasma (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 311-316 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A fully automated assay for the analysis of ranitidine in serum and plasma, with and without an internal standard, was validated. It utilizes robotic solid phase extraction with on-line high performance liquid chromatographic (HPLC) analysis. The ruggedness of the assay was demonstrated over a three-year period. A Zymark Py Technology II® robotic system was used for serial processing from initial aspiration of samples from original collection containers, to final direct injection onto the on-line HPLC system. Automated serial processing with on-line analysis provided uniform sample history and increased productivity by freeing the chemist to analyse data and perform other tasks. The solid phase extraction efficiency was 94% throughout the assay range of 10-250 ng/mL. The coefficients of variation for within- and between-day quality control samples ranged from 1 to 6% and 1 to 5%, respectively. Mean accuracy for between-day standards and quality control results ranged from 97 to 102% of the respective theoretical concentrations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060613
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  • 81
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    Determination of 10α-methoxy-9,10-dihydrolysergol, a nicergoline metabolite, in human urine by high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 9-11 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A specific method for the determination of 10α-methoxy-9,10-dihydrolysergol, a nicergoline metabolite (metabolite 2), in urine is described. Metabolite 2 was well separated from the urine components on a reversed phase column, Hypersil ODS 5 μm, using an acetonitrile: pH 3.5 phosphate buffer (40:60, v/v) as the mobile phase at a flow rate of 1 mL/min. UV detection was set up at 220 nm. After addition of a known amount of lysergamide as the internal standard, the compounds were extracted from alkalysed urine on a pre-packed glass column (Extrelut 1) with dichloromethane. With 0.5 mL urine, concentrations down to 0.56 μmol/L could be determined.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060104
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  • 82
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    Preparation of glycine-conjugated bile acids and their gas/liquid chromatographic analysis on an aluminum-clad flexible fused silica capillary column (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 4-8 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This paper describes a method for the direct gas/liquid chromatographic (GC) analysis of 46 glycine-conjugated bile acids, which differ from one another in the number, position and configuration of the hydroxyl groups at positions C-2, C-3, C-4, C-6, C-7 and/or C-12. Free bile acids were converted quantitatively on a micro scale to ethyl ester-trimethylsilyl (Et-TMS) and methyl ester-dimethylethylsilyl (Me-DMES) ether derivatives of the corresponding glycine conjugates. The Et-TMS and Me-DMES ethers of the glycine conjugates were chromatographed on an aluminum-clad flexible fused-silica capillary column coated with a thin film (0.1 μm) of chemically bonded and cross-linked methylpolysiloxane. Relative retention time (RRT) and methylene unit (MU) values were determined for the 46 compounds and their GC behaviour was discussed. The derivatization procedure and the retention data would be useful for the direct GC identification of unknown glycine-conjugated bile acid mixtures extracted from biological samples.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060103
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  • 83
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    Quantitative determination of valproic acid and 14 metabolities in serum and urine by gas chromatography/mass spectrometry (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 24-29 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A method for the determination of the antiepileptic drug valproic acid and 14 of its metabolites in serum and urine by gas chromatography/mass spectrometry with selected ion monitoring of the trimethylsilylated derivatives has been developed. Sample preparation, including hydrolysis of VPA-conjugates and removal of urea in urine is carried out at pH 5.0 and is rapid and simple. The samples are extracted with ethyl acetate and the concentrated extracts are trimethylsilylated. Analysis with adequate separation of metabolites is achieved with a DB 1701 fused silica (Megabore) capillary column. The method exhibits high recovery and reproducibility and is sufficiently sensitive and selective for analysis of small sample volumes. Application of the method for screening patient serum and urine samples for unusual metabolite patterns, with possible predictive value for early detection of liver injury, is presented.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bmc.1130060108
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  • 84
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    Calendar of events (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 108-108 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060214
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  • 85
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    High performance liquid chromatographic strategy suitable for the analysis of exopolysaccharides extracted from pathogenic bacteria (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 115-119 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A high performance liquid chromatographic (HPLC) method has been developed to permit the rapid comparison of acidic polysaccharides of diverse compositions and the sensitive determination of their constituents. It is based on two combined analyses of the polysaccharide hydrolysates - a separation of the released compounds by ion-moderated partition chromatography with UV detection at two wavelengths and a separation of the sugar dansylhydrazine derivatives by reversed phase chromatography. The former permits identification and quantitation of uronic and carboxylic acids, the latter permits more sensitive and specific determination of the neutral aldoses. Some bacterial exopolysaccharides have been used to demonstrate the validity of this HPLC procedure for the chemical characterization of uronic acid-containing polysaccharides. This method appears to be useful for studying capsular polysaccharides, which are involved in the evasion of phagocytosis by pathogenic bacteria.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060303
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  • 86
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    Analysis of fragrance compounds in blood samples of mice by gas chromatography, mass spectrometry, GC/FTIR and GC/AES after inhalation of sandalwood oilDedicated to Prof. Fleischhacker on the occasion of his 60th birthday. (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 133-134 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: After inhalation experiments with sandalwood oil and the pure fragrance compounds coumarin and α-terpineol, substances were detected and measured in the blood samples of test animals (mice) using gas chromatography/mass spectrometry (GC/MS) (MID) in connection with GC/FTIR (SWC), GC/AES (carbon and oxygen trace) and flame ionization detection/gas chromatography. Using tiglinic acid benzyl ester as the internal standard the following concentrations in serum could be found: α-santalol 6.1 ng/mL, β-santalol 5.3 ng/mL and α-santalene 0.5 ng/mL. In separate inhalation experiments with coumarin and with α-terpineol the corresponding concentrations were 7.7 ng/mL and 6.9 ng/mL, respectively.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060307
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  • 87
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    Sensitive fluorometric detection of prostaglandins by high performance liquid chromatography after precolumn labelling with 4-(N,N-dimethylaminosulphonyl)-7-(1-piperazinyl)-2,1,3-benzoxadiazole (DBD-PZ) (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 143-148 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A highly sensitive and simple method for the determination of prostaglandins (PGs) by HPLC with fluorescence detection is described. PGs are converted to the corresponding fluorescence derivatives by the reaction with 4-(N,N-dimethylaminosulphonyl)-7-(1-piperazinyl)-2,1,3-benzoxadiazole (DBD-PZ) in the presence of 2,2′-dipyridyl disulphide and triphenyl phosphine in acetonitrile. The reaction is completed at room temperature after 30 min. The DBD derivatives of nine PGs are separated within a single 45 min chromatographic run on a reversed phase ODS column with a linear gradient elution using water and acetonitrile. The detection limits (signal-to-noise ratio of 3) calculated from the standard mixture of PGs (6-keto-F1α, F1α, F2α, E1, E2, D2, limaprost, A1 and B1) are in the range 1.7-5.0 fmol. The applicability of the proposed procedure is evaluated to the detection of PGs added to rat plasma.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060310
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  • 88
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992) 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060401
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  • 89
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    Non-labelled benzodiazepines partitioned into synaptosomal membranes: their extraction and quantification by high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 183-190 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A method for the extraction and quantification by high performance liquid chromatography (HPLC) of non-labelled benzodiazepines partitioned into biological membranes has been developed. The benzodiazepine (BZD) was partitioned in a synaptosomal membrane-buffer system. The membranous pellet was separated by centrifugation and from this pellet, previously submitted or not to a proteolytic treatment and resuspended in the same buffer, the BZD was extracted by the addition of the proper volume of ethyl acetate, i.e. that capable of extracting at least 99.5% of the total drug in the aqueous phase. Optimal conditions for maximum proteolysis were: incubation of membranes at a final concentration of 1 mg protein/mL in the presence of 0.08 mg of Protease type I per mL for 90 min. at 45°C. Although the efficiency of the proteolysis was demonstrated not only by kinetic but also by electrophoretic evidence, recovery of BZD in the organic solvent was not increased by the enzymatic treatment at a mass BZD/protein ratio in the range 4-4.6 10-5 μg BZD/mg protein. For the HPLC quantification a reversed phase ODS column was used with methanol: water (1:1) plus 3.5% acetic acid as the mobile phase at a constant pressure and 1 mL/min flow rate. The UV detector was calibrated at 265 nm. Calibration curves were constructed by plotting peak height or peak area vs. nmoles BZD and adjusted to straight lines by a regression analysis by the least squares method. The peak height was selected as the detection method. Intra- and inter-assay precision did not exceed 10% and the total recovery was 100%.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060406
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  • 90
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    Simultaneous determination of pseudouridine and creatinine in urine of normal children and patients with leukaemia by high performance liquid chromatography (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 191-193 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A reversed phase high performance liquid chromatographic method for the simultaneous determination of pseudouridine (PU) and creatinine (Cr) in urine is described. The mobile phase was 0.01 mol phosphate buffer (pH 6.1) containing 2.5 mmol octanesulphonic acid as the ion pairing agent. UV detection was set at 250 nm. Variation in pH value affected the retention time of PU and Cr significantly; Their separation from interfering peaks was also affected. The recoveries of PU and Cr were 89.93% and 90.35%, respectively. The standard deviation of the method for PU was 48.69 ± 0.063 (nmol/μmol Cr, mean ± SD, n = 5). The urine samples from 233 normal children of different ages and 119 patients with leukaemia were analysed by this method. The normal reference value was appraised by comparison with the percentage of immature cells in the bone marrow. The results showed that the sensitivity of the method was 94.12%, the specificity was 95.86%, the accuuracy was 95.50%, the positive predictive value was 82.05% and the negative predictive value was 98.78%. The method can be used to evaluate the state of the leukaemia, and to monitor the effect of treatment.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060407
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  • 91
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    An improved method for isolation and identification of Zn-metallothionein from cadmium-induced rat liver (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 205-211 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Zn-metallothioneins (MT-1 and MT-2) were isolated and purified from Wistar rat liver induced by subcutaneous injection with cadmium chloride over a short time. Instead of Sephadex G-50 and DEAE Sephadex A-50, new chromatographic media produced by Pharmacia, Sephacryl S-200, S-100 and DEAE Sepharose Fast Flow were used in the purification of metallothioneins. The time required for purification with the new method was only 1/3 that required with the usual method and had the same purification effect and rate of recovery. The number of mercapto groups measured with modified Ellman's reagent and cysteine as standard is 20 in MT molecules. Zn and Cd concentrations in each fraction were measured by single sweep polarography rather than atomic absorption spectrophotometry. MT-1 and MT-2 contained 6 gram atoms of zinc, but no cadmium. Purified MT-1 and MT-2 were shown by high performance liquid chromatographic analysis to be highly homogeneous and had an amino acid composition similar to that of Cd-MT.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060411
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  • 92
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    Detection of abnormal haemoglobin by capillary electrophoresis and structural identification (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 224-226 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Haemoglobin obtained from a male adult Ghanian with retinopathy, which was probably caused by haemoglobinopathy was analysed by capillary electrophoresis (CE) for clinical diagnosis. Two major peaks, which were in the ratio of nearly one, were detected. The elution times of these peaks (HbXI and HbXII) were faster than that of normal haemoglobin (HbA). The existence of two different abnormal types of haemoglobin was clear in the patient blood. The following sequence analysis revealed that the first peak (HbXI) was HbC and the second (HbXII) was HbS on the electropherogram, and that the patient was a heterozygote of HbS and HbC (HbSC disease). One of the diagnostic processes in a haemoglobin disease was shown by the combined use of CE, HPLC and a protein sequencer.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060504
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  • 93
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    Quantitative determination of a new anticonvulsant (CGS 18416A) in human plasma using capillary gas chromatography/mass spectrometry (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 236-240 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An analytical method has been developed for the determination of a new antiepileptic drug, CGS 18416A, in human plasma. CGS 18416A is a new anticonvulsant representative of a novel class of water-soluble agents being developed for the treatment of epilepsy. Preclinical trials indicate sustained efficacy at relatively low oral doses, indicating a need for a sensitive assay. The method is based on capillary gas chromatography/mass spectrometry and utilizes stable isotope-labelled CGS 18416A as the internal standard. Samples (1 mL) are acidified, then washed with pentane/ethyl acetate, followed by liquid/liquid extraction at pH 11 with pentane/ethyl acetate. Extracts are then concentrated and analysed directly by gas chromatography/mass spectrometry. Separation is accomplished on a thick film methylsilicone capillary column. Mass spectrometry was carried out under positive ion ammonia Cl conditions with selected ion monitoring of the protonated molecular ions (m/z = 248 and 252) for CGS 18416A and the 13CD3-CGS 18416A, respectively. Specificity was demonstrated by the lack of interfering peaks at the retention time of CGS 18416A and the internal standard. Recovery and reproducibility assessments indicate good accuracy and precision over the validated concentration range of 0.2-51 ng/mL. The limit of quantification is 0.2 ng/mL and the method has sufficient sensitivity to support clinical trials. This is illustrated with an example of quantification in a normal volunteer following oral dosing.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060507
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  • 94
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    Product news (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 106-107 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060213
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  • 95
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    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992) 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060301
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  • 96
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    A sensitive determination method for mexiletine derivatized with dansyl chloride in rat plasma utilizing a HPLC peroxyoxalate chemiluminescence detection system (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 124-127 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A sensitive determination method for a non-fluorescent anti-arrhythmic drug, mexiletine, in rat plasma is presented utilizing a HPLC peroxyoxalate chemiluminescence (PO-CL) detection system. After an internal standard (4-methylmexiletine, 4.35 pmol) and 0.1 N sodium hydroxide solution were added to 5 μL rat plasma, the solution was poured onto an Extrelut 1 column. Both mexiletine and the internal standard were eluted with diethy ether and then the eluate was evaporated to dryness. The residue was dissolved in 0.2 M borate buffer (pH 8.5) and mixed with dansyl chloride (75 nmol) in acetronitrile. After standing of 90 min at room temperature, 0.5 N HCI was added to the reaction mixture to stop the reaction and a 2/45 aliquot of the mixture was subjected to a HPLC PO-CL detection system using bis(4-nitro-2(3,6,9-trioxadecyloxycarbonyl)phenyl)oxalate (TDPO) and hydrogen peroxide. The calibration curve for mexiletine in rat plasma was linear over the range 20-100 ng/mL plasma (20.6-103 fmol/injection). The detection limit (S/N = 2) was 1.0 fmol over the whole procedure. The method was applied to the measurement of the time courses of plasma mexiletine concentration after oral administration of the drug [25 mg (115.9 μmol)/kg] to rats.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060305
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  • 97
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    Calendar of events (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 162-162 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060314
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  • 98
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    Chiral separation by high performance liquid chromatography. I. Review on indirect separation of enantiomers as diastereomeric derivatives using ultraviolet, fluorescence and electrochemical detection (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 163-167 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The increased attention on the therapeutic implications of stereoisomerism has provided an impetus for the development of analytical methods for enantiomeric separation. The indirect method of separation of enantiomers as diastereomers using high performance liquid chromatography (HPLC) has emerged as an efficient and versatile approach. This is due mainly to the availability of numerous chiral derivatization reagents (CDRs). This article reviews CDRs useful for the development of an indirect HPLC method using ultraviolet, fluoresence and electrochemical detection. In addition, factors crucial for the development of the indirect method are discussed.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060402
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  • 99
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    One-step preparation of Hageman factor fragment concentrate (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 194-195 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The Hageman factor fragment (HFf) concentrate was prepared from acetone and dextran sulphate activated human plasma by chromatography on a CM-Sephadex column. The preparation was free of the main kallikrein inhibitors - Cl-inactivator, α2-macroglobulin, antithrombin III and α1-antitrypsin. The HFf concentrate can serve as an activator of prekallikrein in patient plasma.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060408
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  • 100
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    Liquid chromatographic determination of hyoscine (scopolamine) in urine using solid phase extraction (1992)
    New York, NY : Wiley-Blackwell
    Biomedical Chromatography 6 (1992), S. 198-204 
    Details
    ISSN: 0269-3879
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A sensitive method for the determination of hyoscine (scopolamine) in urine is described. After concentration and “clean-up” on C18 and CN solid phase extraction columns, hyoscine was quantified by high performance liquid chromatography with coulometric detection (oxidation at +0.9 V). The limit of detection was 5 ng per sample and the precision for 5 mL samples containing 2 ng/mL was 12.3%. The method was applied to urine samples collected from 12 volunteers wearing Scopoderm TTS patches. The mean excretion rate of unmetabolized hyoscine was 0.45 μg/h and 87% of the total hyoscine was present as conjugates. Apohyoscine (aposcopolamine) was identified as a urinary metabolite. The significance of this with regard to hyoscine assays is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bmc.1130060410
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