|
The problem of pesticide residues has become a global problem, pesticide residues exceeding not only the impact on food safety and people's health, but also brought huge losses to the national economy, strengthen pesticide residue analysis and detection and its degradation has a very important practical significance. Microbial degradation is an efficient, thorough, no secondary pollution become an important way to degradation of pesticide residues. In this paper, high performance liquid chromatography cyhalothrin, beta-cypermethrin and triazophos for quantitative detection of pesticides in drinking water, vegetables and fish in three typical food Spodoptera. Studies have shown that Spodoptera cyhalothrin acetone / hexane, acetone / petroleum ether, acetone / petroleum ether extract better detection of liquid chromatography with acetonitrile / water (v / v: 80/20) type is preferably detected peak, 230nm under the conditions as the mobile phase in pesticide concentration of from 0.1 to 10 ppm, the recovery rate of the three groups of extractant were 97.93% to 103.02%, from 91.4% to 113.9% and 89.58% to 103.22% relative standard deviation in the range of 0.58% to 9.90%; cypermethrin were used acetone / methylene chloride, acetone / petroleum ether, acetone / petroleum ether extract better detection of liquid chromatography using acetonitrile / water (v / v: 80/20) as mobile phase, 225nm under the conditions of detected peak preferably in the pesticide concentration of 0.1 to 10 ppm, the the three groups EXTRACTANTS recoveries were 100.72% to 101.98%, from 98.6% to 115.3% 87.21% to 117.20% and the relative standard deviation in the range of 0.642% to 7.30%; triazophos ethyl acetate, ethyl acetate, acetone extract better detection of liquid chromatography using acetonitrile / water (v / v: 80/20) as mobile phase, preferably 246nm under the conditions detected peak type, in the the pesticides concentration of 0.1 to 10 ppm when the two sets of extractant recoveries were 94.29% to 105.83%, 93.82% to 112.01% the relative standard deviation in the range of 3.46% to 6.87% and 92.67% to 113.02%. The method is simple, fast, can play a positive role in food safety testing. This study were screened by enrichment culture from the the pesticide plant wastewater port orchard soil for of sewage and long-term spraying of pesticides, pesticide-degrading strains, strains screened from soil degradation effect is not ideal, and ultimately isolated from sewage three degradation bacteria F37, ML9 and TF413 degradation of lambda-cyhalothrin, beta-cypermethrin and triazophos. Biolog identification results showed that F37 for Brinell Citrobacter (Citrobacter braaki), the optimal degradation temperature of 37 ° C, the optimum degradation of the initial pH of 7.0, bacteria co-metabolism by degradation of lambda-cyhalothrin, training 72 h 200 mg / L lambda-cyhalothrin the degradation rate of up to 80.88%. ML9 for Acinetobacter (Acinetobacter junii), the optimal degradation temperature of 32 ° C, the optimum degradation initial pH of 7.0, bacteria co-metabolism by degradation of beta-cypermethrin, cultured 84h 400 mg / L beta-cypermethrin degradation rate of up to 70.05 %; TF413 Alcaligenes faecalis (of Alcaligenes faecalis), the optimal degradation temperature of 32 ° C, the optimum degradation initial pH of 7.0, bacteria co-metabolism by degradation of triazophos, cultured 72 h 40 mg / L three triazophos degradation rate of 70.83%. Lambda-cyhalothrin, beta-cypermethrin and triazophos pesticides at pH 5, pH 7 and pH 9 water and sea water degradation dynamics. The degradation rates of the three pesticides in water and the pH of the water, lambda-cyhalothrin, beta-cypermethrin and triazophos pesticide degradation in alkaline water faster the 45d degradation rates of 81.943%, 61.775%, 89.671% slower degradation in acidic water, 45d degradation rate of 52.130%, 47.397%, 73.594%; lambda-cyhalothrin in pH 5, pH 7 and pH 9 water and sea water half-life were 40.77d, 30.14d 16.95d and 32.70d; beta-cypermethrin in pH 5, pH 7 and pH 9 water and sea water half-life were 41.04d, 30.54d, 20.82d and 33.49d; triazophos at pH 5, pH 7, pH 9 water and the half-life in seawater were 22.95d, 17.68d, 13.89d and 19.90d.
|