Determination of Abamectin Residue in Sediment Using High Performance Liquid Chromatography-Tandem Mass Spectrometry

KeyWord:abamectin  HPLC-MS/MS  sediment  pesticide residue

Abstract:

      A high-performance liquid chromatography-tandem mass spectrometric£¨HPLC-MS/MS£© method was developed to analyze abamectin in sediment.The sample was extracted with a mixture of hexane and acetone by ultrasound-assisted microwave extraction,and purified with solid phase extraction column packed with primary/secondary amine and graphite carbon black.The analytes were separated on a Thermo-C18 column£¨50 mm¡Á2.1 mm,1.9 ¦Ìm£© using a mixture of acetonitrile¡Ãacetic acid-ammonium acetate¡Ãwater£¨75¡Ã10¡Ã15£© as mobile phase.The analysis of the target compounds was performed under atmospheric pressure chemical ionization mode with multiple reaction monitoring.The quantification of abamectin was based on internal standard calibration£¨emamectin benzoate as the internal standard£©,and the calibration standards were prepared using matrix matched solution for compensation of matrix effect.The calibration curve of abamectin was linear in the range of 1.6-400 ¦Ìg/L with correlation coefficient£¨r2£© of 0.999 3.The relative standard deviations ranged from 2.2% to 16.2%,and the limit of detection was 0.18 ng/g by dry weight.The established method was used to analyze sediment samples collected from an urban stream in Guangzhou,and the results were compared with those obtained by the HPLC/fluorescence detection after derivatization.Similar results were achieved by both methods,but the HPLC-MS/MS method showed greater sensitivity and simplicity,and was suitable for the detection of sediment-associated abamectin at low concentrations.