Study On Analysis Methods Of Pesticide Residues In Foods By Solid Phase Extraction And Chromatography

The thesis includes three parts. The background and literature summarize(Chapter I ),two solid-phase extraction(SPE) methods of determination for pesticide residues in food coupled with HPLC(Chapter II toIII), and the primary study on analysis the simultaneous determination of multi-pesticide residues in food(Chapter IV to VI).Sample pre-treatment technologies and their application to pesticide residues analysis in foods were reviewed in Chapter I , It is mainly in the solid-phase extraction technology and chromatography method.In Chapter II , an analytical method was studied on the determination of thiophanate-methyl in red pepper by solid phase extraction-high performance liquid chromatography. The sample was cleaned by neutral Alumine SPE cartridges, the pesticide residue was determined by high performance liquid chromatography. The influencing factors included flow rate, cleaning volumes and extraction solvents were discussed. The minimum detectable limit of thiophanate-methyl obtained after extraction was 0.06mg/L.Recoveries of the samples were 76.8%~88. 7%(n=6). The results show the method is effective, quick, simple and suitable for routes.In Chapter III, the analysis method for carbendazim in apple juice using C18 SPE cartridages coupled with High performance liquid chromatography (HPLC) was primarily investigated. The improved sample pre-treatment technology saved costs and time. The recoveries ranged from 92.6% to 108.3% and detection limit was 0.02mg/kg. The method can be used in the determination of carbendazim in juices.In Chapter IV, twenty-three pesticides in cucumber have been analyzed using SPE technology and gas chromatography with ECD. The multi-pesticide included the organochlorin and pyrethroid. The influencing factors included flow rate, cleaning volumes and extraction solvents were discussed. The recoveries were from 70.2% to 108.5%, RSDs were from 0.81% to 3.28%.the detection limits were from 0.03 u g/Kgto 2.06 u g/Kg . At present, this method meets the requirement of domestic industry standard method.In Chapter V , a method has been developed for the analysis of different organochlorine pesticides in Chinese Scutellaria baicaiensis Georgi(Huangqin) using solvent extraction, neutral Alumine cartridges solid phase extraction clean-up and analysis by gas chromatography with an electron capture detector. The pesticides in the study consisted of a-,(3-,y-and 8-hexachlorocyclohexane,/?,/?'-ï¿¡>ï¿¡>ï¿¡>, p,p'-DDE , p,p '-DDT, o,/?'-DDT, hexachlorobenzene, heptachlor epoxide. The recoveries of method were from 78.3% to 102.9%. RSDs were from 0.31% to 2.69% and the detection limits were from 0.26 u g/Kg to 1.69 u g/Kg.In Chapter VI, The determination of 82 pesticide residues in strawberry juice samples is investigated by GC-MS method. Compounds were identified and determined according to their retention times and characteristic ions. The method can be applied to analyze the multi-pesticide residue of produce.