ABSTRACT
A novel method was described for detection carbamate pesticides residue in cucumber by immobilizing acetylcholinesterase enzyme in a micro-screen plate with 96 wells based on GA-BSA-gelatin gels. The concentrations of BSA, GA and gelatin in enzyme immobilization solution were optimized and the best concentrations were 5%, 0.5% and 0.1%, respectively. To analyze the pesticides residue 5g cucumber sample was homogenized with 10 mL acetone then an aliquot of 5mL extract was collected in a 10 mL test tube with a cap, into which 2g sodium chloride and 2mL dichloromethane were added in sequence. After shaking, 1 mL of the supernatant aliquot was evaporated by a blower in a small beaker and dissolved by 20% methanol-water solution then 50 microL was piped to a sample well. After incubation 10 minutes the absorbance was detected. The proposed method offered a rapid, simple and inexpensive means to in screen of batch samples. The minimum detection limit of this method was in a range of 0.1-0.2 mg/kg for cucumber samples.
