| With the rapid development of modern science and technology, the natural phenomena have been studied in depth. The application systems that chemistry researchers are faced become more and more complicated, which makes physical scientist manufacture a large number of multi-channel and high-order analytical instruments. The data produced by the instruments are three-dimensional or four-dimensional data arrays, rather than just simple scaler or vector response data. The data arrays contain useful chemical information, at the same time, including background and interference response, it boosts the development of chemometric multi-way calibration methods. Multi-way calibration can extract useful chemical information from these complex data arrays; they can replace the "physical or chemical separation" with "mathematical separation" strategy through separating the signals of target analytes away from those of uncalibrated background or interferences. The benefit of the method, known as "second-order advantage", is capable to determine the content of analytes of interest even in the presence of unknown interferents. Such methods have shown positive effects on various subjects, especially agricultural chemistry, environmental chemistry, biochemistry and pharmaceutical chemistry, and can provide a variety of powerful techniques to resolve practical difficult problems occurred in these subjects. The research work in this dissertation focuses on the methodologies of multi-way calibration and applying it to quantitation of phytohormones and herbicides.1. Quantitative analysis of phytohormones in agricultural system by using second-order calibration method (Chapter2to Chapter4)Indole-3-acetic acid (IAA) is one phytohormone of the auxin group and is capable of coordinating the overall process of plant growth and development. IAA is active in the very low concentration range. Therefore, it is important to quantify IAA in the low concentration range in complex system. A new spectrofluorimetric method for the direct determination of IAA in soil is proposed and discussed (Chapter2). It combines the fluorescence excitation-emission matrices (EEMs) with second-order calibration methods based on the alternating trilinear decomposition (ATLD) algorithm and the self-weighed alternating trilinear decomposition (SWATLD) algorithm. These methodologies fully exploit the second-order advantage of second-order calibration method, allowing the concentrations of indole-3-acetic acid to be quantified even in the presence of unknown fluorescent interferents in soil samples. Moreover, it has been demonstrated that both algorithms are insensitive to the number of components in complex system.A sensitive excitation-emission fluorescence method with second-order calibration strategy is proposed to simultaneously determine of abscisic acid (ABA) and gibberellin (GA) contents in extracts of leaves and buds of ginkgo (Chapter3). The methodology is based on the alternating normalization-weighed error (ANWE) and the parallel factor analysis (PARAFAC) algorithms, which make it possible that gibberellin and abscisic acid concentration can be attained in extract of plants even in the presence of unknown interference from potential interfering matrix contaminants introduced during simple pretreatment procedure. Satisfactory recoveries were obtained although the excitation and emission profiles of the abscisic acid and gibberellin were heavily overlapped with each other and with background in the plant extracts. The limits of detection obtained for gibberellin and abscisic acid in leaf samples were9.6and6.9ng mL-1, respectively, which were in the concentration range (from hundreds to several ng g-1) for gibberellin and abscisic acid in leaves in different periods. Furthermore, in order to investigate the performance of the developed method, some statistical parameters and figures of merit of ANWE and PARAFAC are evaluated. The method proposed lights a new avenue to determine quantitatively phytohormones in extracts of plants with a simple pretreatment procedure, and may hold potential to be extended as a promising alternative for more practical applications in plant growth process.Kinetin (KT) is a synthetic substance belonging to the cytokinines family.6-Benzylaminopurine (6-BAP) is a common model compound as one of the most important classes of plant hormones—cytokinins. Colchicine is an alkaloid prepared from the dried corns and seeds of colchicum autumnale. A novel method based on high performance liquid chromatography-diode array detection (HPLC-DAD) coupled with SWATLD algorithm is decribed for the determination of kinetin,6-benzylaminopurine and colchicine in extracts of bean and buds of bean and soil samples (Chapter4). Satisfactory results have been achieved for kinetin,6-benzylaminopurine and colchicine in three different complex samples at simple chromatographic condition, fully exploiting the "second-order advantage" of second-order calibration method.2. Second-order calibration method for quantitative analysis of herbicides in environmental system (Chapter5to Chapter6) A rapid non-separative spectrofluorometric method based on the second-order calibration of excitation-emission matrix (EEM) fluorescence is proposed for the determination of napropamide (NAP) in soil, river sediment, and wastewater as well as river water samples (Chapter5). With0.10mol L-1sodium citrate-hydrochloric acid (HC1) buffer solution of pH=2.2, the system of NAP has a large increase in fluorescence intensity. To handle the intrinsic fluorescence interferences of environmental samples, the alternating penalty trilinear decomposition (APTLD) algorithm as an efficient second-order calibration method is employed. Satisfactory results have been achieved for napropamide in complex environmental samples. Furthermore, in order to fully investigate the performance of second-order calibration method, we test the second-order calibration method using different calibration approaches including the single matrix model, the intra-day various matrices model and the global model based on the APTLD algorithm with nature environmental datasets. The results showed the second-order calibration methods also enable one or more analyte(s) of interest to be determined simultaneously in the samples with various types of matrices. The maintenance of second-order advantage has been demonstrated in simultaneous determination of the analyte of interest in the environmental samples of various matrices.A novel application of second-order calibration method based on an APTLD algorithm is presented to treat with the data from high performance liquid chromatography-diode array detection (HPLC-DAD)(Chapter6). The method makes it possible to accurately and reliably analyze atrazine (ATR), ametryn (AME) and prometryne (PRO) contents in soil, river sediment and wastewater samples. Satisfactory results are obtained although the elution time and spectral profiles of atrazine, ametryn and prometryne are heavily overlapped with the background in environmental samples. Furthermore, the accuracy and precision of the proposed method are evaluated with the elliptical joint confidence region (EJCR) test. It lights a new avenue to determine quantitatively herbicides in environmental samples with a simple pretreatment procedure and provides the scientific basis for an improved environment management through a better understanding of the wastewater-soil-river sediment system as a whole.3. Developing a new method for decomposition non-quadrilinear four-way data (Chapter7)A four-way data array deviates from the quadrilinear condition, because of non-linear relationship between signal and analyte concentration, non-multilinear signal for a single sample and non-constant component profiles. The classic algorithms for decomposition four-way data, such as quadrilinear parrel factor analysis (4-PARAFAC), can not treat with these data array. The new method produced in the dissertation can model for non-quadrilinear four-way data (Chapter7). The four-way data array is rearranged into an expanded three-way data array following the non-linear way, then it is decomposed by three-way calibration algorithms, finally the relative spectra and concentration have been attained. Based on these attracted merits, such a novel method may hold great potential to be extended as a promising alternative for the non-quadrilinear four-way data array analysis and high-order calibration. |
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