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  • Analytical Chemistry and Spectroscopy  (12)
  • Column liquid chromatography  (2)
  • Isozymes  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 73 (1987), S. 433-439 
    ISSN: 1432-2242
    Keywords: Hordeum chilense ; Tritordeum ; C-banding ; 6-phosphogluconate dehydrogenase ; Malate dehydrogenase ; Isozymes ; Isozyme markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A study of 6-phosphogluconate dehydrogenase and malate dehydrogenase isozyme expression in Triticum turgidum conv. durum /Hordeum chilense monosomic addition lines has revealed the location of two structural genes, 6-pgd-H ch 2 and Mdh-H ch 1, on chromosome 1Hch of H. chilense. The homoeology between 1Hch and other chromosome of Triticeae related species is discussed on the basis of isozyme gene analysis.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 73 (1987), S. 690-698 
    ISSN: 1432-2242
    Keywords: Hordeum chilense ; Tritordeum ; Esterases ; Glutamate oxaloacetate transaminase ; Phosphoglucomutase ; Isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Polyacrylamide and starch gel electrophoresis of esterase (EST), glutamate oxaloacetate transaminase (GOT) and phosphoglucomutase (PGM) isozymes in Hordeum chilense, Triticum turgidum conv. durum, the amphiploid H. chilense X T. turgidum (Tritordeum), and the durum wheat/H. chilense monosomic addition lines revealed the chromosomal location of one EST locus, two GOT loci and one PGM locus. Loci Est-H ch1 and Got-H ch2 were found on chromosome 6Hch,Got-H ch3 on chromosome 3Hch, and Pgm-H ch1 on chromosome 4Hch. These results lend evidence for the assumed homoeology relationships between chromosomes of Triticeae species.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ion-pair and GPC separations ; Amoxicillin oligomers ; β-Lactam ring polymers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Polymeric substances formed from concentrated sodium amoxicillin in an aqueous solution have been separated using two high-performance liquid chromatographic methods. We used a C18 reversed-phase column with tetrabutylammonium chloride as an ion-pairing agent with an acetonitrile gradient and a TSKgel G2500PWxl column with water as the solvent for gel permeation chromatography. The separated materials, ranging in size from the monomer to the tetramer, have been characterized by functional-group chemical analysis, while the identification of the piperazine-2,5-dione was done using a pure standard. A greater number of peaks which were also better defined were obtained using the ion-pair reversed-phase method, and open and closed beta-lactam ring polymer forms could be distinguished. Using the gel permeation method, only a few monomer, piperazine-2,5-dione, dimer, trimer and combined amoxicillin trimer and tetramer peaks were obtained with water, although those obtained were quite well defined. The data on the time-course of formation of the oligomers and the amoxicillin degradation product were virtually identical by both methods.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Prostaglandins ; C18 Solid phase extraction ; Radioimmunoanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The aim of this study has been the evaluation of an automated system for on-line sample preparation using solid phase extraction and HPLC purification for the measurement of prostanoids in urine. We have established the optimum precolumn and column conditions for this analysis. The manual extraction —HPLC procedure furnishes lower recoveries and higher coefficients of variation than those obtained by the automated on-line procedure. The automated system has been applied to prostanoid analysis of human urine samples from subjects exposed to lead.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The diversity of processes that contribute to an x-ray fluorescence spectrum make it difficult to obtain an accurate estimate of the line intensities needed to determine the sample composition in XRF analysis. The radiative contributions forming the spectrum are produced by the interactions that x-ray photons undergo with the atoms of the sample. Many multiple scattering terms contribute to the continuous portions of spectrum that overlap the lines of interest. The lines themselves are formed by the overlap of many narrow (discrete) contributions and some continuous ones: one ‘primary intensity’ plus several enhancement terms. The lines can also interfere with other neighbouring lines produced in the sample. The resulting spectrum, sufficiently complicated at this stage, is still modified in a complex way by the influence of the detector response and successive digitalization by the multi-channel analyser. The difficulties that such spectral complexity introduces in the process of extracting the ‘primary fluorescence intensity’ from the experimental spectrum can be overcome by using a theoretical spectrum of reference that, in this paper, was calculated using the code SHAPE. Such a theoretical spectrum has the property that all the single contributions are well known, and therefore can be used to estimate correctly the fraction of ‘primary fluorescence intensity’ under any experimental line of interest in the real spectrum enclosed between two given energy channels. Since the theoretical spectrum can be computed only for a known composition, the calculated fraction can be initially obtained by feeding SHAPE with an arbitrary composition. The fraction estimated with the theoretical spectrum is used to correct the corresponding peak area in the experimental measured spectrum, which in turn is used to obtain a new calculated composition. This result is used to feed a new spectrum computation, defining an iterative method that converges to the unknown composition. The theoretical details of this iterative method are described and some experimental examples of EDXRF analysis using this technique are given. The advantages of the method for treating some paradigmatic cases of analysis are also illustrated.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 10 (1981), S. 74-77 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Relative X-ray fluorescent intensity data have been generated numerically for binary samples under mono-chromatic excitation in those cases of absorption plus enhancement that are dealt with in this work. These data were fitted to the empirical Rasberry-Heinrich equation, keeping both coefficients different from zero, since from our numerical calculations it is shown that in most cases the best fit is achieved when A ≠ 0. Furthermore, this approach shows that a third coefficient introduced into the empirical equation improves the fitting. The aforementioned results suggest that the empirical equation could be deduced from the theoretical equation of fundamental parameters under suitable approximation. The result is an equation similar to that of Rasberry and Heinrich, from which analytical approximated coefficients are obtained. It is then possible to calculate a calibration curve using fundamental parameters values.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 15 (1986), S. 103-105 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Equations were obtained from physical theory to express the fluorescence intensity emitted by a sample in terms of the geometrical parameters of a source-sample-detector cylindrical symmetry arrangement. These equations allow the calculation of the optimum sizes of samples in XRF. The thickness required to maximize the detected fluorescence intensity, in terms of the value of the remaining physical and geometrical parameters, was determined. A thin sample in transmission geometry was considered, where excitation is produced by an isotropic monoenergetic x-ray source. The sizes of the detector and source are such that they are considered to be dimensionless compared with the sample. These approximations do not affect the validity of the results.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 24 (1995), S. 283-292 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The nature of the scattering interactions in the x-ray energy regime makes the effect of polarization extremely important, mainly when the incident beam is partially or totally polarized. The effects of the source polarization on the x-ray spectrum are analysed, stressing the points of interest in each case of unpolarized, linearly polarized and circularly polarized excitation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 17 (1981), S. 68-70 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deuteration of 2-phenylthiazolidine, and its complexation with the shift reagent tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionato)europium, have been used to study the signals and conformation of the heterocyclic protons and to interpret the 1H NMR spectrum of this 2-substituted thiazolidine.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 11 (1982), S. 70-78 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: It has been shown that x-ray fluorescence calibration curve coefficients are closely related to matrix effects, such as absorption or absorption plus enhancement of the fluorescent radiation. In the classical paper of Rasberry and Heinrich,1 a single coefficient (named Aik) calibration curve was proposed when pure absorption is the predominant effect on the spectral line of interest. Similarly, and for practical purposes, a single coefficient (named Bik) was also considered when absorption and enhancement are present. We propose a new interpretation of calibration curve coefficients based on analytical expressions obtained recently for binary compounds under monochromatic excitation. Six distinct possible cases of calibration curves arise. Examples of binary compounds for each case are given. The data considered have been computed using the fundamental parameters method which allowed us to study a large number of possible mixtures for an arbitrary monochromatic excitation. Finally, through a different approach we discuss how this analysis could be extended to consider polychromatic excitation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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