Determination of Four Organochlorine Pesticide Residues in Apple by Solid Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry
YU You-yi;YANG Lu;LIAO Xiang;CHENG Ping;WU Sheng-li;LI Hong;College of Geography Science and Tourism, Xinjiang Normal University;Xinjiang Academy of Forestry;
[Aims] A method was developed for the simultaneous determination of four organochlorine pesticides pentachloronitrobenzene, hexachlorobenzene, heptachlor and chlorothalonil residues in apple by solid phase microextraction coupled with gas chromatography-mass spectrometry. [Methods] The optimum extraction conditions such as fiber type, extraction time, extraction temperature, stirring speed and sodium chloride concentration, were determined by orthogonal design, and the pesticide residues were separated and determined by gas chromatographic-mass spectrometry. [Results] The optimal extraction conditions of SPME was carried out at 50 ℃ for 50 min using 65 μm PDMS/DVB fiber with a constant stirring speed of 600 r/min and 10% NaCl. In 0.02-2.00 mg/L, all the four targets could be completely separated with an excellent linear relationship, the correlation coefficients were all above 0.9992.The recoveries and RSD ranged from 83.3 to 93.4% and 2.5 to 8.4%, respectively. [Conclusions] The developed method is simple and rapid, both recoveries and precision can be used in determination of various organochlorine pesticide residues in apple.