The Study On Liquid Phase Microextraction In Analysis Of Organophosphorus Pesticides Of Coastal Environment

Nowadays, research on the pollution of residual pesticides in aquatic ecosystem has been a hot problem. A series of science reports have shown evidence that low concentration level of residual pesticide can perform harmful influence on the aquatic ecosystem. However, methods for analyzing pesticide residuals in environmental samples still have a few problems in quatification. Therefore, for fast monitoring of environmental contamination by pesticides and accomplishment of risk assessment, rapid and sensitive analytical methods are paramount. Liquid-phase microextraction (LPME) is a new method of analyzing organic pollutions in environment. LPME based on solvent extraction method, and contain the advantages of solid-phase microextraction (SPME). LPME is a solvent-minimized, fast, portable extraction method, and it's a new method that combines extraction and sample introduction in one step. This thesis introduced the different types of LPME, and summarizes the application of LPME in the field of chromatogragh. The major study of this thesis was concentrated on the analyzing organophosphorus pesticides (OPPs) in water and sediment by single-drop microextration (SDME), hollow fiber-liquid phase microextration (HF-LPME) and dispersive liquid-liquid microextraction (DLLME). After the comparing of these three extraction methods, the major conclusion were listed as follows:(1) Modified SDME method was feasible when applied to the analysis of OPPs in water sample. Firstly, Experimental parameters impacting the extraction efficiency were optimized. Then, under the optimized conditions, the detection limits (LOD) was 0.012-0.45μg·L-1 (NPD), and relative standard deviation (RSD) was 3.0-6.0%. Compared with other SDME methods for extraction of OPPs in water, the modified method concentrated on improving the stability of extraction solvent. After the modification, a larger volume of extraction solvent and a higher stirring speed could be got during the extraction proceed. With this modification, lower LOD was achieved. (2) HF-LPME was feasible when applied to the analysis of OPPs in sediment sample. Under the optimized conditions, the LOD was 1.3-17.7μg·kg-1 (NPD), and RSD was 2.8-14.4%. Compared with SDME, hollow fiber could separate the extraction solvent from the sample, and the small particles in the sample were unable to enter the extraction solvent. Therefore, the injection port would not be polluted by the particles when injected the extraction solvent. (3) Compared with SDME and HF-LPME method, the advantages of DLLME for analysis of OPPs in water sample were fast and time saved. Under the optimized conditions, the LOD of DLLME was 0.048-0.18μg·L-1 (NPD), and RSD was 2.1-8.6%.