Rapid Analysis Of Complex Samples By GC-MS With The Aid Of Immune Algorithm

Hyphenated chromatography has been widely used for the identification and quantification of the components in complex systems. It has been proved to be powerful methods for both qualitative identification and quantitative analysis. For samples of complex mixtures, highly efficient separation is a common problem, which will make the quantitative and qualitative analysis of the components very difficult. Therefore, extracting target components information from the multicomponent overlapping signals is a challenging and active research field. To obtain a satisfying separation result, the time-consuming sample pre-treatment methods and an optimized experimental condition should be employed. It is, therefore, still necessary to develop efficient approaches of fast analysis for hyphenated chromatography technique. Chemometrics has provided an alternative way for analyzing complex samples by resolving the overlapping signals. In the dissertation, a serie of methods for rapid analysis of components in complex samples by gas chromatography-mass spectrometry (GC-MS) were developed. The proposed methods were applied in analysis of real samples and the feasibility of rapid analysis was also validated. This dissertation includes two main aspects:Much effort has been made to analyze the toxic substances in foods or vegetables due to the interferences in the sample matrix. In this work, taking the determination of prometryn in leek samples and acrylamide in processed food products samples as examples, a simple method was proposed for fast analysis of the components in real samples using GC-MS and chemometric resolution. The purification step in preparing the samples was simplified, and a short capillary column and fast temperature program were employed in GC-MS measurement. Although the measured signal is composed of overlapped peaks with the interferences and background, the signal of prometryn and acrylamide can be extracted by chemometric resolution. Compared with the results by the different quantitative methods, the results obtained by the proposed method were found to be reliable. For the rapid analysis of multicomponent mixtures using GC-MS, a chemometric multistep screening approach was proposed to extract the signals of the components from the overlapping signals measured with a very fast temperature program. At first, independent component analysis was used to find all the possible mass spectra from the overlapping signals in the moving windows along the retention time, and iterative target transformation factor analysis was employed to validate the existence of the extracted spectra from each window. Then, identical signals in the validated spectra were excluded using match ratio as a criterion. Finally, the chromatographic profiles for each spectrum were calculated using non-negative immune algorithm, and the spectra with a reasonable profile were taken as the identified components. A mixture of53pesticides was analyzed with a very fast temperature program of7min. A total of48pesticides and16interferences were identified from the overlapping GC-MS signals.