Dissipation pattern and pre-harvest residue limit of abamectin in perilla leaves

Environ Monit Assess. 2013 Nov;185(11):9461-9. doi: 10.1007/s10661-013-3265-5. Epub 2013 Jun 1.

Abstract

The pre-harvest residue limit (PHRL) of abamectin (abamectin B1a and B1b) in Perilla frutescens leaves grown under greenhouse conditions were investigated using high-performance liquid chromatography with a fluorescence detector. Samples were extracted with acetonitrile. The extract was purified through a solid phase extraction procedure. Then the purified extract was derivatized with trifluoroacetic anhydride and N-methylimidazole to form a strong stable fluorescent derivative of abamectin. Finally, derivatized abamectins were conveyed to the detector via an Atlantis C18 column, with water and methanol as a mobile phase. Calibration curves were linear over the calibration ranges with coefficients of determinants r (2) ≥ 0.999. The limits of detection and quantification were 0.0033 and 0.01 mg kg(-1) for abamectin B1a and B1b, respectively. Recovery was assessed in a control matrix at two different fortification concentrations, with three replicates for each concentration. Good recoveries were obtained for the target analytes and ranged from 82.11 to 93.03%, with relative standard deviations of less than 8%. The rate of disappearance of total abamectin on perilla leaves for recommended and double the recommended doses was described as first-order kinetics with a half-life of 0.7 days. Using the PHRL curve, we could predict the residue level of total abamectin to be 0.92 mg kg(-1) at 7 days before harvest or 0.26 mg kg(-1) at 4 days before harvest, which would be below the provisional MRL designed by the Korea Food and Drug Administration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agriculture
  • Half-Life
  • Insecticides / analysis*
  • Ivermectin / analogs & derivatives*
  • Ivermectin / analysis
  • Perilla / chemistry*
  • Pesticide Residues / analysis*

Substances

  • Insecticides
  • Pesticide Residues
  • abamectin
  • Ivermectin