Study On Hollow Fiber Liquid-Phase Microextraction Combined With Ion Chromatography

As a novel sample pretreatment technology, hollow fiber liquid-phase microextraction(HF-LPME) provides many advantages including low cost, simple, fast and easy to operate. HF-LPME has been widely used in pretreatment for gas chromatography(GC), liquid chromatography(LC) and capillary electrophoresis(CE), but rarely for ion chromatography(IC). In this work, applications of HF-LPME combined with IC in biology, beverage and environment were investigated. The content of this thesis is as follows:1. In biomedical field, the determination of four angiotensin-converting enzyme inhibitors (ACEI) in body fluid was studied by HF-LPME combined with IC. The extraction conditions including selection of organic solvent, pH of donor phase and acceptor phase, salt content, extraction time and stirring rate were optimized. Under the optimal extraction and chromatographic conditions, the concentration factors of four ACEI were from10.8to20.8. Detection limits of the four ACEI were from8μg/L to40μg/L. The relative standard deviation (RSD) ranged from2.05%to4.86%. The recoveries of this method were from83.5%to100.8%. The results demonstrated that this method could eliminate the interference of other impurities in urine samples, and would be used to research drug metabolism of the four ACEI in human body.2. In the field of food and beverages, the determination of phytohormones (indoleacetic acid, salicylic acid, and indolebutyric acid) in natural coconut juice was studied, using HF-LPME combined with IC. The extraction parameters of phytohormones, including selection of organic solvent, pH of donor phase and acceptor phase, salt content, extraction time and stirring rate were optimized. Under the optimal extraction and chromatographic conditions, the concentration factors of indoleacetic acid, salicylic acid, and indolebutyric acid were58,224and110. Detection limits of three phytohormones were from0.6μg/L to1.4μg/L with RSD from3.32% to6.52%. The recoveries of this method ranged from81.1%to103.1%. The analysis of the three phytohormones in natural coconut juice was realized.3. In the field of environment, the determination of aromatic amines (o-toluidine and4-chloroaniline) in waste water was studied, using HF-LPME combined with IC. The extraction conditions including selection of organic solvent, pH of donor phase and acceptor phase, salt content, extraction time and stirring rate aromatic amines were optimized. Under the optimal extraction and chromatographic conditions, the concentration enrichment factors of o-toluidine and4-chloroaniline were88and124. Detection limits of o-toluidine and4-chloroaniline were0.2μg/L and0.5μg/L with RSD at0.85%and3.38%, respectively. The recoveries for spiked water samples ranged from95.0%to106.5%. The results showed that the detection sensitivities of aromatic amines were improved greatly by HF-LPME combined with IC.