Development of a Multiresidue Method for the Analysis of 33 Organochlorine Pesticide Residues in Fatty and High Water Content Foods

A new multiresidue method has been developed and validated for the determination of 33 organochlorine pesticides (OCPs) in various fatty and high water content food matrices. The OCP residues in foods were extracted with matrix solid-phase dispersion and cleaned up with gel permeation chromatography and Florisil solid-phase extraction. The instrumental determination was carried out by a gas chromatograph coupled to a single quadrupole mass spectrometer (MS) with runtime of 11 min. Besides, negative chemical ionization mode was also studied and evaluated for OCPs' sensitivities. The optimized MS was operated in electron ionization mode and acquiring three selected ions per target compound. The method was validated with various food samples, including edible oil, meat, seafood, eggs, coffee, tree nuts, fruits, vegetables, etc. according to SANCO/12571/2013. An adequate linear relationship was obtained in the studied concentration range (0.5-10.0 mu g kg(-1)) in sample; the average spiked recovery values were in the range 70-120 % for the two levels of concentration studied in samples: 0.5 and 2.0 mu g kg(-1). Precision values, expressed as relative standard deviation, were lower than 18 % at aforementioned spiking levels; detection limits and quantification limits were below or equal to 0.1 and 0.5 mu g kg(-1), respectively. Moreover, certified reference materials were used to assess the accuracy of the developed method. Finally, the developed method was successfully applied for the OCPs' determination in real samples for the first Hong Kong Total Diet Study.