The Study On Determination Of Organophosphorus Pesticide And Digestion Dynamic In Vegetables Located At The Xiangjiang River Changsha

Vegetable is one of the most widely used of food consumption in China. In recent years, along with a wide range of organic phosphorus pesticide use, the vegetables growing security risks. Although since January 1,2007, the country banned use five kinds of virulent organophosphorus pesticide such as methamidophos, but the organophosphorus pesticide poisoning incidents still occur. Due to the huge toxic of organophosphate pesticides, there is an urgent need to establish a fast and efficient method for the detection of organophosphorus pesticides and the vegetables with organophosphorus pesticide safety evaluation and study of dynamic. This study selected the five representative vegetable cultivation bases near the Xiangjiang River in Changsha for sample collection. The main findings are as follows:(1) QuEChERS-gas chromatography (QuEChERS-FID) method of methamidophos, parathion, omethoate residues in vegetables was established, the method selected acetonitrile as the extraction solvent at 1,5,10 μg/L,the recovery was 88.43%-96.59% and the relative standard deviation was 3.58%-6.33%, limit of quantization (LOQ) of methamidophos, parathion, omethoate were 0.03,0.05,0.02 μg/L.(2) Selecting three kinds of vegetables of five representative growing areas in Changsha, the average percent of pass of cabbages, cucumbers and tomatoes were 98.60%,97.37% and 97.73% respectively. Experiment were evaluated in pesticide residues and pesticide detection rate, test results analysis and MRLs standard: methamidophos accounted for 52.5% of all detected organ phosphorus pesticides; Five sampling points of organ phosphorus pesticide residues which is the highest Gushan town, the lowest is Dutuo town; The risk of vegetables Yanghu wetland area is bigger than other area. The reason of vegetables pesticide contamination in Changsha is the irrational pesticide product structure, farmers can not reasonably spraying pesticides, and inadequate supervision by national authorities; The adjusting the pesticide product structure, strengthening its training and restructuring of planting vegetables and popularizing no pesticide residues vegetables should be carry out.(3) Experiment study on the dynamic resolution law of three kinds of organophosphorus pesticides in vegetables, methamidophos, parathion and omethoate standard curves were established; This paper studied three organ phosphorus pesticide residues digestion dynamic law in vegetables, the methamidophos, parathion and omethoate pesticide concentration respectively was 75 mg/L,50 mg/L and 100 mg/L. It is concluded that the three kinds of organophosphorus pesticides in three kinds of vegetable’s half-life, dispelling curve, regression curve and dispelling equation, the half-life of the three pesticides in vegetables is range from 1.70 d to 3.24 d; It was studied that the relationship between concentration,pesticide spraying frequency and vegetables of organ phosphorus pesticide residues, the result showed that the more spraying frequency and the greater the concentration of pesticide in vegetables, the greater the amount of pesticide residues in vegetables.