Simultaneous Determination of Dimethenamid, Saflufenacil and their Metabolites in Maize Using a Modified QuEChERS Method and Liquid Chromatography-Tandem Mass Spectrometry

Hydrophilic metabolites of pesticides in food and the environment are seldom analyzed due to thelack of suitable analytical methods. In the present study, a single-run analytical method was developed to determine dimethenamid, saflufenacil and their five metabolites in maize grain and plant. A good linearity was achieved for the matrix-matched calibration curves of the seven analytes with r(2)0.9991. The average recoveries of dimethenamid, saflufenacil and their metabolites in maize grain and plant were 70.1-113.8% with inter-day relative standard deviations 21.5%. The limits of detection and quantification for the two herbicides and their metabolites were in the ranges of 0.008-1.4g/kg and 0.027-4.7g/kg, respectively, in two matrices. The limits of quantification for dimethenamid and saflufenacil in maize grain were below the maximum residue limits proposed by Codex (10g/kg). The results from field trials demonstrated the method effective and reliable for monitoring of the target residues in maize.