Three-way Data Analysis And Its Applications To Chromatographic And Fluorometric Analysis

Chemometrics is a developing composite discipline of chemistry. The main focus of chemometrics is on applying the methods of mathematics, statistics and computer sciences to extracting the optimal scheme for chemical measurements and to elucidating the data collected from chemical measurements. Two important characteristics of modern analytical chemistry are that instrumentation of analytical tools and complication of chemical system. Chemometrics uses the enormous signals generated by the modern analytical instruments, and provides a variety of convenient techniques for quantitative analysis of complex multi-component systems. Especially, second-order calibration methodologies have the second-order advantage, allowing analyte concentrations to be estimated even in the presence of uncalibrated interferents. The chemometric methodologies coupled with analytical instruments can improve or replace the"chemical separation"with"mathematical separation", displaying the characteristic of fast and universal, dependable. It gives active impact on these disciplines of chemistry, especially biochemistry and food chemistry and pharmaceutical chemistry, and also provides a variety of powerful techniques to resolve difficult problems of complex chemical systems. In this paper, the author utilized the instruments such as LCxLC-DAD and HPLC-DAD, EEMs coupled with multi-way data analysis methodologies, and did some work in the research of complex multi-component systems.1. The removal of background drift in LCxLC-DAD measurements (Chapter 2)A novel technique for removal of three-dimensional background drift in comprehensive two-dimensional (2D) liquid chromatography coupled with diode array detection (LCxLC-DAD) data was proposed. The basic idea is to perform trilinear decomposition on the instrumental response data, which is based on the alternating trilinear decomposition (ATLD) algorithm. In model construction, the background drift is modeled as one component or factor as well as the analytes of interest, hence, the drift is explicitly included into the calibration. The method involves performing trilinear decomposition on the raw data, then extracting the background component and subtracting this background data from the raw data, leaving the analytes'signal on a flat baseline. Simultaneous evaluation of three-dimensional background drift and true signals may improve the quality of the data. This method has been applied to the determination and removal of three-dimensional background drifts in simulated multidimensional data as well as experimental comprehensive two-dimensional liquid chromatographic data. It was shown that this technique yields a good removal of background drift, without the need to perform a blank chromatographic run, and requires no prior knowledge about the sample composition.2. The quantitative analysis of complex multi-component systems (Chapter 3 to 6)With the increasing attention on the quality and security of food, analytical measurements with high accuracy and efficiency are required urgently. New analytical techniques are investigated and applied in food analysis. Sudan dyes are synthetic colorants and are widely used in household products such as waxes, floor and shoe polishes. Unfortunately, Sudan dyes are used as synthetic colorants in food illegally. In Chapter 3, the Sudan dyes in hot chilli samples were analyzed with HPLC-DAD. With second-order calibration methodologies such as the self-weight alternating trilinear decomposition (SWATLD), the satisfactory prediction results has be obtained even in the presence of uncalibrated intertering components. The sample preparation was based on solvent extraction, and internal standard was not required. Quantification was carried out with simple mobile phase.Sulfonamides constitute a group of drugs which are widely used in veterinary. Their metabolizing process are slow in animal body, thus, residues of these drugs may remain in food of animal origin. In Chapter 4, a new method based on the use of HPLC-DAD coupled with the alternating penalty trilinear decomposition (APTLD) was applied to the rapid determination of sulfonamides in milk samples. Though the chromatographic and spectral peaks of the components were highly overlapped, the good quantitative results have been obtained owing to the second-order advantage. The application of second-order calibration methodologies provides a new technique to food analysis.Drug analysis in body fluids is an important issue in biomedical field. Chromatographic separation techniques are usually used in drug analysis. In some complex multi-component systems, it is difficult to get completely separation of the components, and inaccuracy results could be obtained. However, the application of second-order calibration methodologies can improve or replace the"chemical separation"with"mathematical separation", displaying the characteristic of fast and universal, dependable.Glucocorticoids are important in predicting against shock, stress, inflammation, etc. It plays an important role in human physiology, and is being a useful marker for the diagnosis under pathologic conditions. Due to the structural similarity between cortisol and prednisolone, it is not surprising that the two analytes have similar spectral profiles and close retention time. In Chapter 5, second-order calibration based on ATLD is employed to determine the concentration of cortisol and prednisolone in body fluids from HPLC-DAD data. In this work, solvent extraction was used in sample preparation, since it is simple and convenient. A simple mobile phase consisting of methanol and water was used. Though heavily overlapped chromatographic peaks of the analytes and interferences were obtained and the spectra of these species were also overlapped, the powerful ATLD algorithm can resolve the overlapped peaks into corresponding chromatographic, spectral and concentration profiles even in the presence of unknown coeluting interferences.Metoprolol, aβ1-selectiveβ-adrenergic receptor-blocking agent, is clinically used in the treatment of arrhythmia, angina pectoris and hypertension. As direct spectrofluorimetric analysis has the characteristic of high sensitivity and selectivity, as well as its relative low cost, in Chapter 6, a new spectrofluorimetric method for the direct quantitive analysis of metoprolol in plasma is presented. It is based on the use of EEMs and second-order calibration algorithms. This methodology enables accurate and reliable measurement of the analyte concentration, even in the presence of unknown and uncalibrated fluorescent components. Simple sample pretreatment step was required.3. Three-way data analysis in the research of pharmaceutical dynamics process (Chapter 7)The study of interactions between drugs and DNA are significant not only in understanding the mechanism of interaction, but also in giving a good guidance for designing new drugs. However, the mechanisms of interactions between molecules and DNA were still little known. In this study, the competitive interactions of THP and EB with DNA were investigated with fluorescent spectrophotometry. Spectroscopic studies, including fluorescent spectra analysis and parallel factor analysis (PARAFAC) of excitation-emission three-way data array were carried out on the competitive interactions of the complex. With PARAFAC, the excitation and emission spectra as well as the relative concentrations of co-existing species in different reaction and equilibrium mixtures can be directly and conveniently obtained. The obtained results showed that THP competed against EB to bind to DNA. The results also indicated that the mode of binding of the complex to DNA was intercalation action. It is valuable for providing a deeper insight into the interaction mechanism of THP and EB with DNA. The PARAFAC algorithm proved a convincing method for studying the competitive interactions of complex with DNA. The application of chemometric methods can provide more intuitionistic information for the mechanism study of drugs and DNA. It also provides a helpful verification for the controversial interaction mechanism between the drugs and DNA.