The Research On Residue Of Dichlorvos And Fipronil In Aquatic Products

For the vast and irrational use of pesticides, the problem of pesticide residue becomes more and more remarkable, especially the pesticides residue in food. Investigation on the pesticide residue of aquatic products has important significance for improving the social safety consciousness of aquatic products, formulating relevant policies and regulations, macroeconomic control measures, producing aquatic products without pollution.Dichlorvos, Fipronil are the pesticides limited by Ministry of Agriculture. Dichlorvos belongs to high toxic pesticide, easy to cause acute food poisoning, so it was qualified residue; Fipronil was limited to use in shellfish aquatic organisms and bees because of the high risk. Therefore, it’s necessary to analysis these two kinds of pesticdes residue in aquatic products. This paper studies the detection methods of Dichlorvos and Fipronil in aquatic products, and applied the methods for testing. Research has obtained the satisfactory results as follows:First, this paper studies the detection method of Dichlorvos in aquatic products using Gas Chromatography. This method uses acetonitrile as extraction solvent to extract Dichlorvos which residues in aquatic products. Then blow the extracted liquid to a certain volume by nitrogen, add some sodium chloride solution (mass fraction is4%), and join10mL n-hexane to remove fat. At last, use ethyl acetate to extract Dichlorvos in the mixed liquid, constant volume and tested by GC. By the method established in this paper, the recovery is between80.2%-112.9%, the relative standard deviation (RSD) is less than7.3%, the determination of limits of detection (LOD) is about2.0μg/kg. The linearity, precision of this method meets the requirements of pesticides residue analysis. In addition, we applied the method to test the samples of Monopterus albus, the results suggest the residue of Dichlorvos is in good condition.Then, this paper studies the detection method of Fipronil in aquatic products using Gas Chromatography. This method uses acetonitrile as extraction solvent to extract Fipronil which residues in aquatic products, adds n-hexane to remove fat and some Weak-polar impurities. Then concentrates acetonitrile by rotary evaporation, uses mixed liquid of acetone:hexane (3:7) to dissolve. Dissolved liquid gets through the PSA column and collects the filtering liquid and eluant. Concentrates the liquid by rotary evaporation, constant volume by lmL acetone and tested by GC. By the method established in this paper, the recovery is between75.6%-109.8%, the relative standard deviation (RSD) is less than6.4%, the determination of limits of detection (LOD) is about0.2μg/kg. The linearity, precision of this method meets the requirements of pesticides residue analysis.What’s more, we applied the method to test the samples of Monopterus albus, the results suggest the residue of Fipronil is in good condition.At last, this paper studies the residues dynamic of Fipronil in Cipangopaludina chinensis Gray. The test lasts15days, puts Cipangopaludina chinensis Gray into water with different concentration of Fipronil, then samples at different time, the samples is detected by the method we set up. The results show that Fipronil was enrished in Cipangopaludina chinensis Gray, when it returned to the normal environment, there appeared phenomenon of elimination.