Abstract:

A new method was developed for the determination of pesticide residues in crucian carp using on-line gel permeation chromatography-multi gas chromatography/mass spectrometry (GPC-MDGC/MS). The pesticide residues were extracted with cyclohexane-ethyl acetate (1:1, v/v) for twice. After being frozen, the extract was filtered by 0.22 μm member, and then cleaned up and analyzed by online GPC-MDGC/MS. The pesticides were selectively transferred from the 1st column to the 2nd column by means of heart cutting. As a result, selective transfers of some pesticides from the first to the second dimension were at times essential to avoid overlapping. The selected separation conditions from the study with standards were applied to crucian carp spiked with some pesticide standards. The performance of this method was examined by recovery, linearity and precision. Inter-standard quantitative method was used for calculation. Good linear relationship was achieved in the range of 0.01-0.9 mg/L for the 14 pesticides with correlation coefficients above 0.99. The recoveries of the method ranged from 83.0% to 112.9% with the relative standard deviations (RSDs) among 3.2%-12.0% at 3 spiked levels of 0.01, 0.05 and 0.1 mg/kg. This is a simple, rapid method for the analysis of multiple pesticide residues in crucian carp with high accuracy and sensitivity. The results prove that the employment of a multidimensional analysis technique permits to avoid interferences of the analytes with matrix components.

Key words: crucian carp, mass spectrometry, multi gas chromatography, on-line gel permeation chromatography (GPC), pesticide residues