Application Of Kinetic Spectrophotometric Methods For Analysis Of Some Complex Environment And Food Systems

Differential spectrophotometric method for dynamics determination is a fast, simple and sensitive analytical approach, commonly applied in simple analysis for two or three components. However, in complex systems, even if some substances are masked by some agent, it is still difficult for quantitatively analysis, such as food and environment samples. In order to resolve the problem, appropriate chemometrics mathematical statistic methods are introduced, then the effective analysis is implemented for complex multi-component system. The basic principle of the proposed method is as follows:the same reagent act with a variety of analytes. Their nature are different because of the different structure, the reaction rate has a certain different degree. When the added substance is excessed, the reaction can be regarded as pseudo-first-order reaction. In this case, the reaction rate is only linearly related to the concentration of added analytes, then quantitative methods was implemented based on the measured data. In most cases, due to the analytes with similar chemical properties, the differences of the reaction rate between these analytes is relatively small. Thus, some suitable chemometrics method can be used to resolve this problem. The quantitative analysis can be realized by building a multivariate calibration model for multi-component complex systems.In this paper, different kinetics-chemometrics-UV spectrophotometric method was applied to analyze for multi-component systems. The main applications of chemometrics methods were partial least squares (PLS), principal component regression (PCR) and artificial neural networks (ANN); The analytical complex systems, including environment and food objects, were selected as the analytical systems in this research work. In the thesis, four complex systerms were determined, including chemometrics-inhibition kinetic determination of pirimicarb and oxamyl in environmental water samples, silver anoparticles preparation using zntioxidant propyl gallate and its analytical application, kinetic spectrophotometric simultaneous determination of aminophenol isomers by partial least squares, and kinetic-chemometrics determination of avermectins in animal tissues and milk samples. At the same time, the mechanism of kinetic reaction was investigated and discussed, the parameters that could affect the experiment results were optimized, the calibration curve at different concentrations were examined for analytes, the calibration-prediction models were built to determine the synthetic samples, and the related models were established and used for determination of real samples. The feasibility of the method (kinetic spectrophotometric combined with chemometrics for determination multi-components in complex systems) was explored, and the results resolved by built calibration model were compared.