A Novel Enantioseparation and Trace Determination of Chiral Herbicide Flurtamone Using UPLC-MS/MS in Various Food and Environmental Matrices Based on Box-Behnken Design

The detection method for flurtamone enantiomers in soil and five farm products (wheat, maize, sorghum, soybeans and pea) was established using modified QuEChERS method combined with ultra-high-performance liquid chromatography tandem triple quadrupole mass spectrometry (UHPLC-MS/MS). The Box-Behnken design (BBD) of response surface methodology was used to optimize the enantioseparation parameters of flurtamone on Chiralpak IG-3 column. The absolute configuration was first confirmed by the specific rotation and electron circular dichrometry (ECD). The elution order was confirmed as R-(-)-flurtamone and S-( +)-flurtamone with the resolution (Rs) of 4.10 on Chiralpak IG-3 column. Under optimal conditions, the average recoveries in six matrices ranged from 78.2% to 115.7%. The intraday relative standard deviations (RSDs) were less than 11.9%, and the interday RSDs were less than 7.9% for the two enantiomers. The limit of quantitation (LOQ) was 0.005 mg kg(-1) for flurtamone enantiomers in six matrices. Finally, the method was applied to study the enantioselective dissipation of flurtamone enantiomers in soil. R-(-)-flurtamone was dissipated faster than S-( +)-flurtamone in soil, causing the EF of the enantiomers changing from 0.50 to 0.42 in 28 d. The method for residue analysis of flurtamone in food and environmental samples was established for the first time and applied to actual samples. The proposed method provides reliable technical support for food sample analysis and environmental risk assessment of flurtamone.