Rapid determination of organochlorine pesticides in fish using selective pressurized liquid extraction and gas chromatography-mass spectrometry.

A rapid automated extraction and cleanup method using selective pressurized liquid extraction was developed and validated for 14 organochlorine pesticides in fish. The lipid-removal efficiencies achieved by adding alumina, Florisil, acid-treated silica gel, and silica gel to the extraction cell were determined and optimized. In the optimized method, fish (2-3g) was placed above alumina (30 g) in the extraction cell, then the sample was extracted using a 7:3 mixture of hexane and dichloromethane. The method was validated using certified reference materials (NIST SRM 1946 and 1974c), spiked fish, and four lipid-rich fish samples. The mean low- and high-concentration spike recoveries were 91% and 93% with RSD<20%, respectively. Measured concentrations of target OCPs showed good agreement with the certified concentrations in certified reference materials. It suggests the good accuracy and precision of the SPLE method. The proposed method met the most important requirements of an extraction and cleanup procedure, including having a short preparation (cleanup and concentration) time and minimal sample contamination and being able to be automated.