Determination of difenoconazole in vegetables samples by gas chromatography-mass spectrometry using multi-walled carbon nanotubes as solid-phase extraction sorbent

A method based on multiwalled carbon nanotubes(MWCNTs)as the solid phase extraction material had been developed for the determination of difenoconazole in vegetables by gas chromatography-mass spectrometry(GC-MS).The samples were extracted with ethyl acetate,purified by MWCNTs solid phase extraction;and determined by GC-MS. Effects of different extraction solvents and amount of MWCNTs on the determination of difenoconazole were investigated. The results showed that difenoconazole had a good linearity in the range of 0.005~2.0 μg/mL and the correlation was 0.9997 under the optimal conditions. The limit of detection for difenoconazole was 0.001 mg/kg. Tests of recoveries were made by the addition to blank vegetable sample at three spiked levels of 0.01,0.10 and 1.00 μg/mL,and the recoveries were in the range of 84.2%~111.3% with relative standard deviations(RSD,n=5)of 5.3%~11.9%. Therefore,the developed method is suitable for determination of difenoconazole in vegetables qualitatively and quantitatively with satisfactory sensitivity,selectivity,accuracy and precision.