| Flumethrin belongs to pyrethroid pesticides which is mainly used to prevent theectoparasites of livestock through inhibiting theri oviposition and the eggs incubation. It isalso widely used in the prevention and treatment of bee mites. Because of its toxic tocustomers’ health, it is urgent to develop a sensitive and high efficient way to detectresidue of flumethrin in honey.With flumethrin as detecting objects, the method of pretreatment method and thetechnique of high performance liquid chromatography (HPLC) to the flumethrin of honeywere studied in the present paper. There are two main contents:(1) The optimization ofmethod to extract and purify the flumethrin from honey, which provides a new way fordetection of trace analytes in complex substrate;(2) The establishment of method to detectflumethrin by HPLC. At last, the method has applied in the detection of flumethrin residuein the honey samples from the several regions of our country.The main results are as follows:1.The pretreatment method of flumethrin in honey was built and optimizedThe effect of acetone with different volumes on extraction efficiency of flumethrinwas studied to determine the best volume of6mL of acetone in present study. And theeffect of different extractions on extraction efficiency was also analyzed, then n-hexaneand dichloromethane was lastly confirmed the best choice. Moreover, the volume ratiobetween the two extraction was optimized for4:6(n-hexane: dichloromethane), whichmake the extraction efficiency up to more than90%.Solid phase extraction(SPE) was applied to purify the sample based on the extractionmethod. The type of extraction column, and the type and volume of drench lotion andeluent were investigated in our study. Finally, the Oasis HLB was chosen. Methanol withvolume of6mL was used as the drench lotion, acetonitrile with volume of6mL was as theeluting agent, in which condition the recovery of flumethrin was above of80%.2.The method of flumethrin by high performance liquid chromatography(HPLC) wasbuiltA method for detecting of flumethrin residue in honey by HPLC was developed. Theeffect of different ratio of mobile phase on separation effects was analyzed by using XTerraMS C18column. At last, the quick separation was achieved in4.9minutes when thedeteacetonitrile and water with volume ratio of90to10was used as the mobile phase, thedetecting wavelength was267nm, the flow rate was1.4ml/min, the column temperature was30℃, and the volume of injection was20μL. There was a good linear relationshipbetween peak area and concentration of injection in0.1-4.0μg/mL for flumethrin, with thecorrelation coefficients(r2) of1.0000. The mean recoveries for flumethrin were between80.8%and96.8%on three spiked levels of0.2,0.5,1.0mg/kg, and with coefficients ofvariation ranged from0.6%to1.5%. The detection limit for flumethrin was0.005mg/kg,lower than0.01mg/kg which was set by Agricultural industry Standard of the People’sRepublic of China（NY/T1243－2006）.3. Investigation and analysis of honey samples from the part regions of the countryA total of195samples were collected from different regions, including sevenprovinces(Gansu, Anhui, Jiangsu, Zhejiang, Henan, Hubei, Guangdong) and oneautonomous region(Xin jiang).135samples were detected by HPLC.76samples weredetected with flumethrin,59ones were not detected,the detection rate was77.6%.Our result demonstrated that the HPLC had good repeatability and high sensitivity indetection the flumethrin residues in honey, satisfied the analysis of residues, which was anew method to detected flumethrin residues in honey. The method was successfully appliedto detecting flumethrin residue in the honey from several regions of our country andprovided an important theoretical and practical basis for monitoring of residues in beeproducts and protect people’s health. |
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