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The Phytoesterase rapid detection of pesticide residues operation is simple, rapid, sensitive, practical, low cost and are widely used, but are extracted from food crops phytoesterase. This study measured and seven kinds of food crops and forage plants six kinds esterase total activity and specific activity, the results showed that the specific activity of alfalfa esterase, and therefore determine alfalfa suitable phytoesterase source. Design single-factor test, influencing factors determine phytoesterase extracted; obtained by orthogonal test, the optimum extraction process of the alfalfa plant esterase, and alfalfa esterase preliminary purification. The minimum detection limit of alfalfa esterase Rapid detection of organophosphorus and carbamate pesticide residues in vegetables, cabbage organophosphorus pesticide and carbamate pesticides were determined. Extracted from rice, millet, barley, corn, oats, flour, soybeans, alfalfa, golden pheasant children, chinensis, clover, Setaria and lobular Chapter phytoesterase and determination of enzyme activity and specific activity the screening phytoesterase source. The experimental results show that the alfalfa plant esterase activity is soybean esterase 1.34 times, the flour esterase 1.43 times, so choose alfalfa suitable phytoesterase source. 2, orthogonal experiment method extractant type and pH, temperature, time, solid to liquid ratio of five factors on enzyme activity and specific activity to determine the best extraction process: 4 ° C under grinding homogenate fresh alfalfa leaves, 1:10 (m / v) solid-liquid ratio of raw, pH 7.0, 0.1 mol L -1 phosphate buffer solution, shock for 10 min at 4 ° C for filtration, 4000 6 000r · min-1 speed cryogenic centrifugal filtrate 15 min. 3 alfalfa esterase, of wheat esterase and soybean esterase cabbage in the omethoate, monocrotophos, methamidophos, phorate, methyl parathion and other organophosphate pesticides carbofuran carbamate pesticide methomyl 2 sensitivity comparison test, the test results show that the alfalfa plant esterase omethoate, monocrotophos, methamidophos, phorate, methyl parathion 5 the limit of detection of the organophosphorus pesticide carbofuran, methomyl carbamate pesticide were 0.024,0.050,0.009,0.003,0.002,0.013,0.250 μg · mL -1 , and alfalfa esterase sensitivity of these pesticides is higher than wheat of esterase and soybean esterase. When the the pesticide concentrations 0.001 0 .100 μg · mL -1 range, the inhibition rate of pesticide concentration in a straight line to the logarithm of the relationship. Spiked recovery experiments show that higher recoveries, 90.2% 1 18.3%. 4, ammonium sulfate fractionation of alfalfa esterase preliminary purification, the study results show that 60% ammonium sulfate precipitation isolated alfalfa esterase activity increased to 2.6 times the original activity recovery was 31.53% times. 5, to establish the use of alfalfa esterase rapid detection of organophosphorus and carbamate pesticide residues in vegetables and summer earth winter greenhouse production of tomatoes, cucumbers, celery, leeks, cabbage, rapeseed were detected using the method eggplant, peppers, cabbage, beans and other 10 kinds of vegetables, pesticide residues, found that greenhouse vegetable pesticide residues exceeding serious. 6, a preliminary study of the esterase enzymatic properties of alfalfa. The alfalfa esterase in temperature to 40 ° C, the minimal loss of enzyme activity under pH 7.0 weak alkaline conditions, but poor thermal stability, and stored at -20 ℃ can slow down esterase inactivation. 120 days to just 30% of the remaining vitality stored at 4 ℃, and stored at -20 ℃ 300 days still 36% remaining vitality. Alfalfa esterase can be long-term storage at -20 ℃ not completely inactivated. Thawed ready for use, but it can not be repeated freeze-thaw.
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