Stereoselective separation and pharmacokinetic dissipation of the chiral neonicotinoid sulfoxaflor in soil by ultraperformance convergence chromatography/tandem mass spectrometry.
A method for simultaneous enantioselective determination of fenarimol and nuarimol in apple, grape, cucumber, tomato, and soil was developed using liquid chromatography-tandem mass spectrometry. The enantioseparation results of the two fungicides through three different cellulose-based chiral columns are discussed. The influence of column temperature on the resolution of the enantiomers of the two fungicides was examined. Complete enantioseparation of the two fungicides' enantiomers was obtained on a cellulose tris(4-methylbenzoate) column (Lux Cellulose-3) at 25 °C using methanol and 0.1 % formic acid solution (80:20, v/v) as mobile phase. The linearity, matrix effect, recovery, and precision were evaluated. Good linearity was obtained over the concentration range of 1-500 μg L(-1) for each enantiomer in the standard solution and sample matrix calibration solution. There was no significant matrix effect in apple, grape, cucumber, or tomato samples, but signal suppression was typically observed with the soil extracts. The mean recoveries, repeatability, and reproducibility were 76.5-103 %, 2.1-9.0 %, and 4.2-11.8 %, respectively. The limit of quantification for enantiomers of the two fungicides in fruits, vegetables and soil was 5 μg kg(-1). Moreover, the absolute configuration of the enantiomers of fenarimol and nuarimol was determined from a combination of experimentally determined and predicted electronic circular dichroism spectra.