Chemical Multi-Way Calibration Methods For Food Quality And Safety Research

Chemometrics is an interdisciplinary subject that combines chemistry with mathematics,computer science,statistics,and other disciplines.Its research scope basically covers all fields of analytical chemistry.Chemometrics is a powerful tool for data mining and processing,from optimizing the experimental design to processing high-dimensional data of complex systems.As a promising field in chemometrics,chemical multidimensional calibration has been widely used in biology,medicine,environment,food,and materials.Chemical multi-dimensional calibration can use its own"second-order"or"high-order"advantages to assist a variety of modern high-order analytical instruments,simplify or replace chemical/physical separation with mathematical separation methods,and make analytical methods greener and more efficient.There are many types of food and complex ingredients.In recent years,food safety and quality problems have occurred frequently,attracting attention.Therefore,it is very important to develop convenient,efficient,and accurate food analysis methods.No matter how food analysis problems and analytical instruments change,the core task of food analysis is to identify and judge the properties of food by acquiring enough measurement data.The development of chemical multi-dimensional calibration theory is relatively complete,and different calibration models can be constructed according to different data structure types.Through the multi-dimensional calibration model,valuable information can be extracted to the maximum extent from the massive data information for qualitative and quantitative analysis,so as to solve the quantitative analysis problem in a complex system where multiple unknown interferences coexist.This is destined to play an important role in the field of food analysis.In this paper,the combination of excitation-emission matrix fluorescence（EEMs）and chemical multi-dimensional correction is applied to the field of food safety.The main research content is the illegal addition of health products,functional drinks,and rice.The main contents are as follows:In Chapter 2:The second-order calibration method based on the self-weighted alternating trilinear decomposition（SWATLD）algorithm combined with the strategy of excitation-emission matrix fluorescence（EEMs）was used to quantitatively analyze the illegally added sulfamethoxazole（SMZ）and trimethoprim（TMP）.With industrial development,air quality has deteriorated,many people have bad living habits,and the number of people with throat discomfort is increasing.Some unscrupulous merchants will illegally add antibiotics to the throat-clearing health care products in order to make their products achieve immediate results.Such products are seriously harmful to the health of consumers.Both TMP and SMZ have strong endogenous fluorescence,but there are few reports on quantitative analysis of the two by fluorescence method,and only a few kinds of literature have performed fluorescence analysis on one of them.The analytical strategy proposed in this chapter can still accurately quantify two analytes in complex nutraceutical matrices even when the analyte spectra are severely overlapped and the unknown fluorescence background interferes severely.Parameters such as spike recovery,quality factor,and intra-day to-day precision were satisfactory for both analytes.Compared the strategy proposed in this chapter with the classical LC-MS/MS,there is no significant difference between the two by t-test.However,the strategy proposed in this chapter does not require complex preprocessing,and only requires simple ultrasonic extraction,which is more convenient and efficient.In Chapter 3:A second-order correction method based on alternating normalized weighted residuals（ANWE）algorithm was combined with EEMs for simultaneous quantitative analysis of illegally added tadalafil（TADA）and terazosin hydrochloride（THY）in functional beverages.Consumers of functional beverages are mostly male,so many businesses illegally add chemicals with specific efficacy to energy drinks to make their products have the so-called aphrodisiac effect.However,randomly added chemical drugs will accumulate in the consumer’s body,which will lead to a variety of adverse drug reactions.The fluorescence spectra of TADA and THY overlap each other,and there are unknown and variable fluorescence interferences in functional beverages.Nevertheless,with the"second-order advantage"of the proposed strategy,accurate excitation,emission spectral information,and relative concentration information of TADA and THY can still be obtained.In the spiked samples of functional beverages,the spike recoveries of both TADA and THY were in the range of 95%-105%.In addition,the quality factor of the proposed strategy is calculated,and intra-day and inter-day precision experiments are performed to further evaluate the proposed method.Computational results show that the proposed method can be used for the rapid and simultaneous quantitative analysis of illegally added THY and TADA in functional beverages in the presence of unknown fluorescence interference coexistence and overlapping analyte spectra.In Chapter 4:The strategy of using alternating trilinear decomposition（ATLD）algorithm to assist EEMs was used for the direct,rapid and accurate quantification of two fluorescent whitening agents（C.I 351 and C.I 85）added in rice.With the"second-order advantage"of multi-dimensional correction and the high sensitivity of fluorescence detection,even if the fluorescence spectra of C.I 351 and C.I 85 have severe collinearity and unknown fluorescence interference,this strategy still does not require sample analysis.The correct qualitative and quantitative information of the analyte of interest can be extracted by performing complex and tedious concentration and purification steps.Therefore,this analysis strategy can effectively avoid analyte loss caused by tedious preprocessing steps,reduce errors and save time and cost required for analysis,while still obtaining accurate quantitative results and satisfactory quality factors,the spiked recoveries of C.I 351 and C.I 85 were all around 100%,and the LODs were 2.2 ng m L^-1 and 1.0 ng m L^-1,respectively.And through intra-day and inter-day experiments,it has good repeatability and reproducibility.