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  • 1
    Electronic Resource
    Electronic Resource
    Application of artificial neural networks in multifactor optimization of an FIA system for the determination of aluminium (2000)
    Springer
    Fresenius' journal of analytical chemistry 366 (2000), S. 17-21 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A methodology based on the coupling of experimental design and artificial neural networks (ANNs) is proposed in the optimization of a new flow injection system for the spectrophotometric determination of Al(III) with Arsenazo DBM, which has for the first time been used as chromogenic reagent in the quantitative analysis of aluminium. An orthogonal design is utilized to design the experimental protocol, in which three variables are varied simultaneously. Feedforward-type neural networks with faster back propagation (BP) algorithm are applied to model the system, and then optimization of the experimental conditions is carried out in the neural network with 3-7-1 structure, which have been confirmed to be able to provide the maximum performance. In contrast to traditional methods, the use of this methodology has advantages in terms of a reduction in analysis time and an improvement in the ability of optimization. The method has been applied to the determination of Al(III) in steel samples and provided satisfactory results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050004
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  • 2
    Electronic Resource
    Electronic Resource
    FI spectrophotometric determination of Pd with DBOK-chlorophosphonazo (1999)
    Springer
    Fresenius' journal of analytical chemistry 363 (1999), S. 117-118 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A flow injection method was developed for the determination of palladium, based on the reaction of palladium with DBOK-chlorophosphonazo with a detection limit of 0.07 μg/mL and a linear calibration range from 0.1 to 3.2 μg/mL of palladium. The reaction product has a maximum absorption at 630 nm. The method was applied to determine Pd2+ in catalysts and in anode mud samples. The relative error is less than 3% and the recovery of palladium is in the range 95% to 105%
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160051151
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of IO 3 − by flow injection analysis with 5-Br-PADAP and SCN− (1991)
    Springer
    Microchimica acta 103 (1991), S. 279-283 
    Details
    ISSN: 1436-5073
    Keywords: flow injection analysis ; 5-Br-PADAP ; iodate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper reports that a red-violet triatomic ion association is formed by protonated 2-(5-bromo-2-pridylazo)-5-diethylamino-o-phenol, IO 3 − and SCN− in 1.2 mol/l H2SO4. A rapid spectrophotometric flow-injection method has been developed for the determination of IO 3 − based on the association reaction. Various parameters were optimized. The method is applied to kelp solution and satisfactory results were obtained. The limit of detection for IO 3 − is 6.0 × 10−7 mol/l with a sample throughput rate of 84 h−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01243264
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of microamounts of palladium(II) by extraction method without usual organic solvents (1996)
    Springer
    Microchimica acta 122 (1996), S. 143-149 
    Details
    ISSN: 1436-5073
    Keywords: extraction ; water soluble polymer PEG2000 ; microamounts of palladium ; spectrophotometric determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The favorable distribution equilibrium of the complex of Pd(II)-5-Cl-PADAB between the two phases of PEG2000-(NH4)2SO4-H2O extraction system was investigated. The extraction efficiency (%E), distribution coefficient and concentration factors are studied. Spectrophotometric characteristics of the complex in such a system are stable. This method was used to determine micro-amounts of palladium(II) in secondary alloys of Ni. This method of extraction overcomes many disadvantages of methods using usual organic reagents as solvents. It is a convenient, rapid, economical way.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01252416
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  • 5
    Electronic Resource
    Electronic Resource
    Spectrophotometric flow injection determination of trace iodide in table salt and laver through the reaction of iodate with 3,5-Br2-PADAP and thiocyanate (1997)
    Springer
    Fresenius' journal of analytical chemistry 357 (1997), S. 1002-1005 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new simple, rapid and sensitive spectrophotometric flow injection method for the determination of trace iodide is described based on an ion associate of iodate (IO3 –) with 2- (3,5-dibromo-2-pyridylazo)-5-diethylamino-phenol (3,5-Br2-PADAP) and thiocyanate (SCN–). In a strongly acidic medium, this unstable violet product was formed with an absorption maximum at 605 nm. Flow injection is an ideal method to reproducibly monitor the transient signal. Various parameters were optimized using the Super Modified Controlled Weighted Centroid Simplex Method (SMCWC). Under the optimum experimental conditions, iodide could be determined in the range of 1.00 × 10–6 and 2.4 × 10–5 mol l–1. The correlation coefficient of the calibration curve is 0.9991. With a sampling frequency of 80 h–1, the detection limit for iodide is 5.0 × 10–7 mol l–1. The proposed method has been applied to the determination of trace iodide after oxidizing I– in table salt or laver to IO3 –. In addition, the mechanisms of the ion association reaction was studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050292
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  • 6
    Electronic Resource
    Electronic Resource
    Application of a modified simplex method to the multivariable optimization of a new FIA system for the determination of osmium (2000)
    Springer
    Fresenius' journal of analytical chemistry 368 (2000), S. 780-785 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A methodology based on the coupling of experimental design and a modified simplex method is proposed for the optimization of a new flow injection-kinetic system for the spectrophotometric determination of Os (IV) with m-acetylchlorophosphonazo, which has for the first time been used as chromogenic reagent in the quantitative analysis of this element. An orthogonal array design is utilized to design the experimental protocol, in which six variables are varied simultaneously, and obtain the initial simplex using 25 experiments. A modified simplex method is applied to continuously optimize the data of the orthogonal array design; the search for optimum conditions of ¶6 variables using the modified simplex method required only 25 experiments. The efficiency and simplicity of the coupling of the experimental design and the modified simplex method are attractive for the development of new analytical methods. The method has been applied to the determination of Os (IV) in a refined ore as well as in a secondary alloy and provided satisfactory results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160000577
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  • 7
    Electronic Resource
    Electronic Resource
    Evaluation of nonlinear modeling based on artificial neural networks for the spectrophotometric determination of Pd(II) with CPA-mK (2000)
    Springer
    Fresenius' journal of analytical chemistry 367 (2000), S. 215-219 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new method is proposed for the spectrophotometric determination of Pd(II), based on the reaction of Pd(II) with 2-(4-chloro-2-phosphonophenylazo)-7-(3-carboxyphenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid(CPA-mK) in sulfuric acid without heating. Beer’s law is obeyed for 1.0–4.0 μg of Pd (II) in 10 mL of solution. The calibration curve from 1.0 to 42.0 μg in 10 mL of solution is modeled successfully by artificial neural networks (ANNs). The maximum relative error between experimental values and the values predicted by ANNs is 1.5%. In comparison with some mathematical functions, ANNs show better ability for curve fitting, thus greatly extending the applicable range of the calibration curve of this new system. The method has been applied to determine Pd (II) in ore and catalyst samples with a relative error of less than 4% and with a recovery range between 94% and 103%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160000339
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  • 8
    Electronic Resource
    Electronic Resource
    Microdetermination of proteins using m-carboxychlorophosphonazo as detection probe by enhanced resonance light scattering spectroscopy (2000)
    Springer
    Fresenius' journal of analytical chemistry 368 (2000), S. 715-719 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Proteins can be determined using a common spectrofluorometer to detect the intensity of resonance light scattering (RLS). Under acidic conditions, the reaction between m-carboxychlorophosphonazo (CPA-mK) and proteins enhances the weak light scattering of CPA-mK drastically. This enhanced intensity is proportional to the concentration of proteins. The linear ranges for human serum albumin are 0.5–35.0 μg/mL, with detection limits of 0.104 μg/mL. The method yields results comparable to those of the calorimetric method using Coomassie Brilliant Blue G-250 (CBB) with relative standard deviations of 0.72–2.10% (n = 10). There is almost no interference by amino acids and most of the metal ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160000563
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  • 9
    Electronic Resource
    Electronic Resource
    Capillary zone electrophoresis for the determination of average hydrodynamic velocity and diffusion coefficient (1999)
    Springer
    Fresenius' journal of analytical chemistry 365 (1999), S. 499-503 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The determination of the average hydrodynamic velocity and diffusion coefficient by capillary zone electrophoresis is described. The present simple method only requires basic experimental data, such as peak area, peak height and migration time to complete the task of determining the diffusion coefficient and the average hydrodynamic velocity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160051512
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  • 10
    Electronic Resource
    Electronic Resource
    Finite Element Analysis of the Dominant Mode Variation in Groove Guide (2000)
    Springer
    International journal of infrared and millimeter waves 21 (2000), S. 63-76 
    Details
    ISSN: 1572-9559
    Keywords: groove guide ; dominant mode ; finite element method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In this paper, the dominant mode in groove guide is analyzed by finite element method. For the guide with a shallow groove, the electric field lines (abbreviated as E lines) are perpendicular to the parallel plate, which is different from the literatures, and the dominant mode distribution is irrelevant to the groove width; for the guide with a narrow but deeper groove, the E lines are parallel to the plate region, which represents the characteristics of lower attenuation, for the guide with a deeper and wider groove, a complicated E lines are obtained. These results reveal that the dominant mode distribution in groove guide is varied, which replenish our understanding of groove guide, and the results have important values in design, manufacture, and application of groove guide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006642904457
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