Development Of Gas Chromatography Methods For Determination Of Chlorodimeform And Amitraz Residues In Muscle Of Fish

Chlorodimeform and amitraz are two highly effectively insecticide.Both and their intermediate metabolites are highly toxic and can cause potential damage to human health through food chain.Chlorodimeform and amitraz were reconsidered as highly toxic drugs and t prohibited to application by the ministry of agriculture and the ministry of health. The effective methods for the determination of residue of both drugs were established not only to provided support for the detection of prohibited drugs in aquatic products but also guarantee the safety of aquatic animals,plants and the health of consumers.In the experiment of testing of chlorodimeform residue in muscle of Hypophtha-Imichthys molitrix and eel,the optimized sample treatment and analysis conditions for gas chromatography(GC) were selected.After alkalization,the sample was extracted with ethyl acetate,the organic phase was abstracted,concentrated,dissolved with hexane and Cleanup by a Florisil cartridge.The residue was dissolved with hexane and analyzed by capillary gas chromatography-nitrogen-phosphorus detector.The linear range was from 0.05μg/mL to 2.0μg/mL and r was 0.9998.The average recoveries were 82.4%～89.14% when samples were spiked with from 5.0μg/kg to 50.0μg/kg.The detection limit was 3μg/kg.the intra-day and inter-day precisions were less than 12.8%.In the experiment of testing of amitraz residue in muscle of Ctenopharyngodon idellus and eel was established by optimized sample treatment and analysis conditions for gas chromatography(GC). Amitraz was extracted with methanol and partitioned with n-hexane.After the drug was hydrolyzed and derivatived with HFBA,the derivatives were analyzed by capillary gas chromatography-electron capture detection.When the split-less injection was carried out at 250℃,the detector temperature was at 300℃,the oven temperature program was as flow:initial temperature at 50℃,hold for 0.5min,and then programmed at 7℃/ min to 220℃,hold for 5 min.Nitrogen(99.999%) at a flow-rate of 30mL/min was used as auxiliary gas for the electron capture detector,the column flow-rate was 1.0 mL/min.The linear range was from 2μg/L to 200μg/L and r was 0.9995.The average recoveries were 78.6%～90.5%when samples were spiked with 5.0μg/kg,20μg/kg and 200μg/kg.The detection limit was 5μg/kg.the intra-day and inter-day precisions were less than 18.1%.The two methods could met the requirements of the ministry of agriculture and applicant in future in China.