Enantioselective separation of the carfentrazone-ethyl enantiomers in soil, water and wheat by HPLC.

A simple enantioselective HPLC method was developed for measuring carfentrazone-ethyl enantiomers. The separation and determination was accomplished on an amylose tris[(S)-alpha-methylbenzylcarbamate] (Chiralpak AS) column using n-hexane/ethanol (98:2, v/v) as mobile phase at a flow rate of 1.0 mL/min with UV detection at 248 nm. The effects of mobile-phase composition and column temperature on the enantioseparation were discussed. The accuracy, precision, linearity, LODs, and LOQ of the method were also investigated. LOD was 0.001 mg/kg in water, 0.015 mg/kg in soil and wheat, with an LOQ of 0.0025 mg/kg in water and 0.05 mg/kg in soil and wheat for each enantiomer of carfentrazone-ethyl. SPE was used for the enrichment and cleanup of soil, water, and wheat samples. Recoveries for two enantiomers were 88.4-106.7% with RSD(r) of 4.2-9.8% at 0.1, 0.5, and 1 mg/kg levels from soil, 85.8-99.5% with the RSD(r) of 4.4-9.6% at 0.005, 0.025, and 0.05 mg/kg levels from water, and from wheat the recoveries were 86.3-91.3% with RSD(r) below 5.0% at 0.2, 0.5, and 1 mg/kg levels. This method could be used to identify and quantify the carfentrazone-ethyl enantiomers in food and environment.