Applications Of Novel Calibration Models To Quantitative Analysis Of Food And Environmental Samples

The rapid development of modern analytical instruments makes it much easier than ever before to acquire a large enough data for quantitative analysis of a sample.However,the extraction of useful information from large data is becoming more and more difficult due to the increasing complexity of the samples and diversity of data types.And hence,methods for extracting useful information from complex data are highly desired.The raw data of a sample collected by instruments have contributions from not only the analytes of interest but also some interfering factors such as measuring conditions,sample’s physical properties and background interference(s)etc.Without being properly addressed,these interfering factors will affect the quantitative results of the analytes of interest in complex systems.With a view to solving the problem mentioned above,researchers in our laboratory have developed an advanced multiplicative effects model.The multiplicative effects model has been further extended and developed into two new calibration models,i.e.,the quantitave fluorescence ratio model(QFM)and generalized multiple-internal-standard method(MEMGMIS)for quantitative analysis of complex systems using fluorescence spectroscopy and LC-MS,respectively.In this thesis,the two new calibration models are combined with fluorescence spectroscopy and LC/MS to realize accurate and quantitative analysis of the analytes of interest in the complex systems.The details are as follows:In Chapter 2,quantitative fluorescence model(QFM)was combined with 2,3-diaminonaphthalene(DAN)to directly quantify NO2-in environmental water samples.DAN can react with NO2-to form 2,3-diaminonaphthalene triazole(NAT).The reaction results in significant changes in fluorescence measurements from which QFM can extract quantitative information of NO2-.Experimental results showed that the proposed method could obtain quantitative results comparable to those obtained by HPLC.The proposed method for the quantification of NO2-has features of simplicity,good accuracy,high selectivity and sensitivity,and is expected to be develop into a routine quantitative method for NO2-in environmental water samples.In Chapter 3,CdTe quantum dots with good water solubility and stability were synthesized by using mercaptopropionic acid as stabilizer.Carbon quantum dots(C-dots)with high fluorescence quantum yield were synthesized by using sodium citrate as sole carbon source via a microwave assisted route.And then a generalized wavelength-ratiometric probe for detecting Cu2+ was fabricated by incorporating CdTe quantum dots with C-dots(serve as a reference).Accurate accurate quantitative analysis of Cu2+ in soil samples was achieved by combining the generalized wavelength-ratiometric probe with QFMGRP.In Chapter 4,the combination of LC-MS and generalized multiple-internal-standard method(MEMGMIS)was tentatively applied to the quantitative analysis of five food additives in the two kinds of drinks.Experimental results revealed that MEMGMIS could correct the detriment effects of signal instability on the quality of quantitative results of LC-MS,and hence maintain the long-term effectiveness of calibration models established for LC-MS assays.