Determination of clomazone and acetochlor residues in soybean ( Glycine max (L.) Merr.)

The Soybean (Glycine max (L.) Merr.) is a kind of oilseed crop and also a good source of nutrition for human beings, poultry and other animals. Clomazone and acetochlor are two kinds of pesticides of great concern that are widely used to protect soybean from weeds. The purpose of this study was to evaluate the food safety of soybean after applying clomazone and acetochlor. For this purpose, the contents of clomazone and acetochlor in green soybean, green straw, mature soybean, and mature straw collected from six locations in different provinces of China were determined by ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The recoveries of the compounds at different concentration levels were 86%-110% while the relative standard deviations (RSDs) ranged from 2% to 31 11%. The limits of quantification (LOQs) for each matrix of the two herbicides were 0.01 mg/kg. Residues of clomazone and acetochlor in soybean at harvest time were all below 0.01 mg/kg at the recommended dosage.