[Simultaneous determination of 16 organophosphorous pesticides in vegetables, fruits and tea by gas chromatography coupled with clean-up by mesoporous alumina as solid-phase extraction adsorbent].

A gas chromatographic method based on solid-phase extraction was developed for the simultaneous determination of 16 organophosphorous pesticides in vegetables, fruits and tea, including cabbage, lettuce, pumpkin, onion, tomato, turnip, apple, pear and tea. The samples were extracted with ethyl acetate, and clean-up with mesoporous alumina as solid-phase extraction adsorbent. The separation of target compounds was performed on a DB-1701 capillary column, and the quantitative analysis of the organophosphorous pesticides was carried out by gas chromatography with flame photometric detection. The results showed that the calibration curves of the 16 organophosphorous pesticides were linear in the range of 10-2 000 microg/L with good correlation coefficients (R2 > 0.997). The recoveries of the pesticides in different samples at three spiked levels ranged from 83.2% to 103.8% with the relative standard deviations of 2.0%-9.9%. This method has high sensitivity, high accuracy and good repeatability, and can be applied to the determination of the organophosphorus pesticide residues in vegetables, fruits and tea.