Development of a multi-residue enantiomeric analysis method for 9 pesticides in soil and water by chiral liquid chromatography/tandem mass spectrometry

A novel and sensitive chiral liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous measuring individual enantiomers of 9 pesticides including herbicides, insecticides, and fungicides in soil and water. The separation and determination were performed using reversed-phase chromatography on an amylose chiral stationary phase, a Chiralpak AD-RH column, under gradient elution using a mixture of ACN-2 mM ammonium acetate in water as the mobile phase at 0.45 mL/min flow rate. The effects of three cellulose-based columns and three amylose-based columns on the separation were also investigated. The QuEChERS (acronym for Quick, Easy, Cheap, Effective, Rugged and Safe) method and solid-phase extraction (SPE) were used for the extraction and clean-up of the soil and water samples, respectively. Parameters including the matrix effect, linearity, precision, accuracy and stability were undertaken. Under optimal conditions, the mean recoveries for all enantiomers from the soil and water samples were ranged from 77.8% to 106.2% with the relative standard deviations (RSD) less than 14.2%. Good linearity (at least R-2 >= 0.9986) was obtained for all studied analytes in the soil and water matrix calibration curves over the range from 2.0 to 125 mu g/L. The limits of detection (LOD) for all enantiomers in the soil and water were less than 1.8 mu g/kg or mu g/L, whereas the limit of quantification (LOQ) did not exceed 5.0 mu g/kg or mu g/L. The results of the method validation confirm that this proposed method is convenient and reliable for the enantioselective determination of the enantiomers of 9 chiral pesticides in soil and water. (C) 2013 Elsevier B.V. All rights reserved.