title: Dissipation pattern and pre-harvest residue limit of abamectin in perilla leaves.
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.
authors.affiliation: Natural Products Chemistry Laboratory, Biotechnology Research Institute, Chonnam National University, Gwangju, 500-757, Republic of Korea.
authors.forename: Md Musfiqur
authors.initials: MM
authors.lastname: Rahman
authors.forename: Tae Woong
authors.initials: TW
authors.lastname: Na
authors.forename: A M
authors.initials: AM
authors.lastname: Abd El-Aty
authors.forename: Jong-Hyouk
authors.initials: JH
authors.lastname: Park
authors.forename: M N U
authors.initials: MN
authors.lastname: Al Mahmud
authors.forename: Angel
authors.initials: A
authors.lastname: Yang
authors.forename: Ki Hun
authors.initials: KH
authors.lastname: Park
authors.forename: Jae-Han
authors.initials: JH
authors.lastname: Shim
mesh_terms: D000383:Agriculture; D006207:Half-Life; D007306:Insecticides / Q000032:analysis*; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000032:analysis; D031343:Perilla / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis*
chemical_list: D007306:Insecticides; D010573:Pesticide Residues; C048324:abamectin; D007559:Ivermectin