Detection of fenthion residues in Hami melon and its degradation behavior in soils
In this experiment,the residues of fenthion and its metabolite fenthion sulfone were detected and analyzed by gas chromatography-mass spectrometry(GC-MS)in Hami melons of different origins in Xinjiang and in environmental samples(water samples and soils)of the cultivation sites.The different samples were extracted with organic solvents,cleaned-up by a solid phase extraction(SPE)column,eluted with acetonitrile+toluene,and concentrated for detection.The average recoveries in soil,water and Hami melon samples ranged from 82.3%to 104.1%with the relative standard deviations(RSD)of 1.3%-7.9%,and the linearity was good in the concentration of 0.1-2.0 mg/L(r2>0.999).It was found that only in the soil samples,fenthion residues were present.Examining the degradation pattern of fenthion in soil,by the established method,the degradation rate of fenthion on the 35th day after the test was 91.1%under light condition and 70.6%under light-avoidance condition,and the light condition could accelerate the degradation rate of fenthion in soil.The method established in this study was suitable for the determination of fenthion and fenthion sulfone residues in environmental samples(soil and water)and Hami melon,and the methodological results met the standards for pesticide residue analysis.