| Organophosphorus pesticides,as a broad spectrum insecticide with broad insecticidal spectrum,short residual effect period and high efficacy,are widely used in the field of disease and insect control of water and agricultural products.The low price and good insecticidal effect of trichlorfon and dichlorvos have intensified the abuse of trichlorfon and dichlorvos in aquaculture,resulting in pesticide residues in aquatic products and endangering public health.Strengthening the research on the detection technology of pesticide residues in water and agricultural products is of great significance to the safety of water and agricultural products quality and the life safety of consumers.With the increase of technical means,the detection methods of pesticides are more diversified,but the complex components and more accurate analysis are still the difficulties of residue detection.In this experiment,a more convenient and rapid method for extracting trichlorfon and dichlorvos from aquatic animal tissues was established,and the complex methods used in most literatures were compared.The method of directly extracting trichlorfon and dichlorvos by using ethyl acetate at a ratio of 1:5 eliminates the inconvenience of water removal after pure water extraction.This method is more convenient and stable,and the obtained samples are pure,which is more suitable for the detection by external standard method.A method for the determination of Trichlorfon and dichlorvos in edible tissues of Macrobrachium rosenbergii and Croaker by gas chromatography was established.The target drug was separated by DB-5MS capillary gas chromatography column,monitored and analyzed by electronic capture detector(ECD),and quantified by external standard method.In the range of 2.5～50 μg/kg and 4～80 μg/kg,the peak area had a good linear relationship with the concentration,and the correlation coefficient(r)was greater than 0.99.The detection limits and quantification limits of trichlorfon in the large yellow croaker and Roche spermatogenesis were determined by gas chromatography to be 1 μg/kg and 2.5 μg/kg,respectively.Trichlorfon in add 2.5 μg/kg concentration level,the average recovery was 90.60%～103.49% and 89.09%～98.90%,within the group of coefficient of variation were 3.12%～5.23% and 1.53%～5.17%,between the variation coefficient were 4.52% and 3.93% respectively.At 5 μg/kg concentration,the average recoveries of trichlorfon were 91.64%～105.47% and 89.04%～104.01%,the intra-batch variation coefficients were 4.10%～5.23% and 2.13%～6.81%,and the inter-batch variation coefficients were 5.10% and 5.86%,respectively.At 25 μg/kg concentration,the average recoveries of trichlorfon were 90.47%～101.11% and 89.98%～104.43%,the intra-batch variation coefficients were 3.32%～5.55% and 2.37%～5.57%,and the inter-batch variation coefficients were 4.24% and 5.12%,respectively.The detection and quantitative limits of dichlorvos in Yellow croaker and Roche spermatogenesis by gas chromatography were 2 μg/kg and 4 μg/kg,respectively.At 4 μg/kg concentration levels,the average recoveries of dichlorvos were 93.12%～101.82% and 89.8%～99.37%,the intra-batch variation coefficients were 2.13%～4.46% and 1.72%～5.50%,and the inter-batch variation coefficients were 3.36% and 4.01%,respectively.In 8 μg/kg concentration adding level,the average recovery of dichlorvos were 90.36%～101.48% and 86.11%～101.53%,within the group of the variation coefficient was 2.74%～5.06% and 2.74%～5.24%,between the group of the variation coefficient were 4.45% and 5.29% respectively;At 40 μg/kg concentrations,the average recoveries of DDVP were 86.92%～99.41% and 93.05%～101.82%,the intra-batch variation coefficients were 3.74%～6.26% and 1.62%～4.93%,and the inter-batch variation coefficients were 5.08% and 3.46%,respectively.The results showed that the gas chromatography method for the detection of dichlorvos and dichlorvos in edible tissues of fish and shrimp was simple,convenient,rapid,sensitive and accurate.Meet the requirements of veterinary drug residue analysis. |
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