10％噻吩磺隆可湿性粉剂在小麦和土壤中的残留动态研究

Residue dynamics of 10 % thifensulfuron methyl in wheat and soil

为了解噻吩磺隆使用后在小麦及其环境中的残留情况,采取振荡提取、固相萃取净化和高效液相色谱残留检测方法,测定了田间施药条件下噻吩磺隆在小麦植株和土壤中的消解动态及其最终残留情况。结果表明,噻吩磺隆峰面积与质量浓度在0.012 53～5.025mg/L范围内呈线性关系,相关系数达0.999 7。在土壤、小麦植株和籽粒上该农药的平均回收率分别为87.57%～90.70%、89.39%～95.90%、84.17%～89.32%,满足残留检测的要求。田间试验结果表明:噻吩磺隆在小麦植株和土壤中的半衰期分别为4.62～5.33 d和7.70～9.90 d;按推荐剂量施药,成熟时收获的小麦籽粒中噻吩磺隆的残留量均为未检出。研究表明,该药属易分解农药(T_d<30 d),按推荐使用剂量使用是安全的。

This paper is aimed to evaluate the safety level of thifensulfuron methyl by analyzing its residue after applied to the wheat field. Oscillation extraction, solid-phase extraction and high performance liquid chromatographic （HPLC） have been used in the residue analysis. The pesticide residual concentration and its dynamics and residues in wheat and soil were evaluated. Linear range of thifensulfuron methyl was within 0.012 53 5.025 mg/L and the con＇elation coefficient was 0.999 7. The pre-treatment method of soil, wheat plant and grain were different. The average recoveries of thifensulforan in soil, wheat plant and grain were 87.57% - 90.70%, 89.39%-95.90% and 84.17%- 89.32% respectively. These resuits showed that the method has met the requirement of pesticide residue analysis. Field trials were conducted in Changsha and Qufu. With the time increasing, thifensulfuron-methyl residues gradually declined. The degradation was in accordance with the regression equation. When the applied herbicide concentration was 33.75 g/hm^2, the degradation dynamic equation was respectively y = 0. 131 e - 0.09, and y = 1.201e^-0.13x in the soil and wheat plant in Changsha. The half-time for each of them was 7.70 and 5.33 respectively. The degradation dynamic equation were y = 0. 147e^-0.08x （2007） and y =0.169e^-0.07x （2008） in Qufu＇s soil. On the other hand, the degradation dynamic equation for pesticides in soil were y = 1.176e-^-0.14x（2007） and y = 1.599e^-0.15x （2008）. When the wheat-straw was treated by thifensulfuron nmthyl wettable powder at 225 g/hm^2 （effective ingredient is 22.5 g/hm^2） , the residue in kernel was undetected. The result implied that thifensulfuron methyl belongs to non-persistent pesticides （ Td 〈 30 d）. Applying thifensuluron methyl at recommendatory dosage is environmentally secured in China.