砷形态分析用的固相萃取—毛细管电泳偶合系统研究

Study on the speciation of arsenic has been interesting. Capillary electrophoresis (CE) has a lot of merits, such as high efficiency, fast separation and low sample consumption. But low concentration sensitivity limits its application. In this project large-volume field-amplified stacking injection (LV-FASI) with polarity switching was applied to investigate the speciation of arsenic. Using 25 mM phosphate (pH 6.5) and 20 mM phosphate-10 mM borate (pH 9.28) as the buffer solution, the enrichment factor of 34-100-fold was obtained for four arsenic species respectively. The detection limits lie in the range of 0.018-0.093 μg/ml. CE with indirect laser induced fluorescence (LIF) detection was also applied to study the speciation of arsenic. Using fluorescein sodium salt as the probe, the optimal analytical condition, i.e. 2.0 mM sodium bicarbonate (pH9.28) with 10-7 M fluorescein as the buffer, was obtained. The detection limits for the four arsenic species lie in the range of 0.12-0.54 μg/ml.Because of high salt, high protein and a large amount of metabolized products in complex biological fluids, it is very difficult for CE to analyze the trace analytes in them. an off-column sample preconcentration setup, Micro-column Solid Phase Extraction setup (MicroSPE), was firstly developed. The setup is especially suitable for CE because of its low sample consumption and high enrichment efficiency. The setup coupled with CE was respectively used to concentrate and purify sulindac in urine and retinoic acid isomers in plasma. The obtained enrichment factor for each species was larger than 260-fold and 100-fold, respectively. The sample matrices were also purified obviously. The results showed that the MicroSPE setup is suitable for the determination of trace analytes in biological fluids with great sensitivity improvement and matrix removal.The end-column amperometric detection method of CE was also investigated. The method for analyzing 8-hydroxydeoxyguanosine (8-OHdG, an important product of DNA damage) in urine was set up. Combining the dynamic pH-junction concentration method of 8-OHdG in capillary zone electrophoresis with the end-column amperometric detection and solid phase extraction, the detection limit of 2 nM for 8-OHdG was obtained..Besides, the basic theory and the optimization method of the separation conditions were investigated by using chemometrics. A simple and accurate method, current-abruption method, was developed to determine the electroosmotic mobility. Wavelet neural network and genetic algorithm for separation optimization of amino acids derivatized with 2- (9-carbazole) ethyl chloroformate by micellar electrokinetic chromatography was also investigated.

本项目拟研制出一根在入口处装液相色谱填料的专用毛细管电泳柱及其配套方法，通过固相萃取和毛细管电泳的在线偶合及对缓冲液的最佳化，解决体液中砷形态分析难题。本项目成功后，在生化及环保上均有重大意义。