Application Of Second-order Calibration Algorithms Coupled With Three-dimensional Fluorescence In Food Science

In the introductory part of this thesis, the background and history of chemometrics and its research advances are illustrated. The second-order calibration in chemometrics was a core field with mighty advantages, which included the development of the trilinear decomposition algorithms. The applications of chemometrics in food analysis field are briefly illustrated subsequently. Lastly, the development of three-dimensional fluorescence coupled with chemometrics as well as its applications to quantifiy the analytes of analytical interest in complex matrix are introduced.In Chapter 2, a noval method was proposed for simultaneous determination of Tyrosine (TYR) and Tryptonphan (TRY) by combining three-dimentional fluorescence with second-order calibration based on the alternating trilinear decomposition algorithm. Moreover, this method has also been used for simultaneous direct determination of TYR and TRY in amino acid oral liquid with satisfactory results. The results showed that this algorithm could solve the problem of serious fluorescence spectral overlapping of the sought-for analytes and determine simultaneously them even in the presence of uncalibrated interferents.In Chapter 3, an excitation-emission matrix fluorescence (EEMs) method combined with chemometrics methods was also utilized to detect directly Aspartame in beverage. Aspartame is a synthetical sweetener, which can produce methanol in the process of degradation in vivo, so the determination of aspartame in beverage is very important. It was showed that this method is able to handle the occurrence of interference not modeled in the calibration set, which presents"second-order advantage".In Chapter 4, a combination of EEMs with second-order calibration was applied for determination of phenol and thymol in honey. Phenol is an antibiotic drug, which has damage to human cell and respiration centre as well as kidney and nerve system. Thymol is used as disinfector in beekeeping. Although not toxic, thymol residues can devalue honey quality. Hence the determination of phenol and thymol in honey has a vitally important meaning. The method was used for direct determination of phenol and thymol in honey by combining excitation-emission fluorescence with second-order calibration based on the alternating penalty trilinear decomposition algorithm. The satisfactory results can be gained even in the presence of complex matrix, which contains some uncalibrated interferences. In Chapter 5, a newly method developed for detecting capsaincin in chilli sauce. Besides nutritional component, colour, lustre and shape, piquancy is the most important factor to evaluate capsicum, So the determination of capsaincin has a vitally important meaning. A selfweighted alternating trilinear decomposition algorithm was utilized to three-dimensional excitation-emission matrix fluorescence data analysis for second-order calibration. This method has been satisfactorily applied to determinate capsaincin in presence of unknown interferents.