Applications Of Novel Quantitative Models In Food And Drug Analysis

The increasing diversity of analytical measurements and complexity of samples causes the conventional calibration models to be less effective in quantitative analysis of complex systems. Hence, advanced calibration methods are needed to realize accurate quantification of analytes of interest in complex samles. To address this issue, our research group proposed a novel multivariate calibration model-multiplicative effects model (MEM), which can slove some difficult problems encountered in quantitative analysis of complex systems. In this thesis, the two novel models have been combined with flourescence spectroscopy and liquid chromatography-mass spectrometry to realize accurate quantitative analysis of analytes of interest in complex samples. This thesis focuses on the further development of the MEM model and its application in areas of food and drug analysis. The main contents of this thesis include the following aspects:In Chapter 2, The MEM model was used to solve the problem of variation in enhancement factors during quantitative analysis of complex systems using surface-enhanced Raman sepctroscopy, which is influenced by the physical properties of the enhancing substrates (e.g., the size and shape of colloids, the degree of aggregation). The combination of the MEM model with SERS technique was succesffully applied to the rapid and accurate quantitation of tiopronin in enteric-coated tablets.In Chapter 3, a multiplicative effects model for generalized multiple-internal-standard method (MEMGMIS) was proposed. When multiple internal standards are used in the simutaneous quantification of several analytes of interest in complex systems by LC-MS, the proposed MEMGMIS model takes full use of all the information carried by multiple internal standards during the quantification of target analytes in complex systems, and hence can more effectively solve the signal instability problem of LC-MS over time cause by variations in ionization efficiency and background interferences. Simutaneous accurate quantitative analysis of five edible artificial colorants in two kinds of cocktail drinks was achieved by LC-MS with the aid of the MEMGMIS model.In Chapter 4, the MEM model was combined with ratiometric flourescence indicator Mag-fura-2 to quantify Mg2+ in health care products. Exprimental results showed that the MEM model could effectively correct the scattering and absorption effects on fluorescence measurements caused by the presence of scaterers and absorbers in turbid media, and hence achieved quite accurate direct quantitative analysis for Mg2+ in health care products without any pretreatment.