噻吩磺隆的残留分析及其在玉米田的残留规律研究

Residue Analysis of Thifensulfuron-methyl and the Residue Dynamics in Corn Field

建立了噻吩磺隆在土壤、玉米和玉米植株中的超声提取、固相萃取净化和高效液相色谱-质谱联用[SPE-HPLC-ESI(+)-MS]残留检测方法,测定了在田间施药条件下噻吩磺隆在土壤中的消解动态及其在土壤、玉米和玉米植株中的最终残留。土壤、玉米和玉米植株样品经乙腈-磷酸盐缓冲溶液(pH7.8)浸泡、涡旋并超声提取后,经固相萃取柱净化,用反相高效液相色谱-质谱检测。结果表明,噻吩磺隆在该方法下的最小检出量为0.2ng,在10倍浓缩倍数条件下的最低检出浓度为2μg/kg,定量限为6μg/kg,平均添加回收率为77.9%～100.4%,变异系数在1.6%～6.5%之间。田间试验结果表明:噻吩磺隆在土壤中的半衰期分别为0.92～1.23d;按推荐剂量施药,距施药时间40d后和玉米收获时,在土壤、玉米和玉米植株中均未检出噻吩磺隆。

A SPE-HPLC-ESI（ ＋ ）-MS method for the determination of thifensulfuron-methyl residues in soil,corn grains and plants was developed. Residue dynamics in soil and the final residues in soil, corn grains and plants were evaluated. The residue of thifensulfuron-methyl in samples （corn grains ,plants and soil） was extracted by a mixture of acetonitrile and phosphate buffer （pH 7.8） =2： 8（V/V） ,vortex and ultrasonic, and then the extracts were adjusted to low pH and passed through a C18 solid phase cartridge under vacuum condition,the elution was concentrated under nitrogen, the determination and quantitation were performed by HPLC-ESI-MS. The minimum detectable amount of thifensulfuron-methyl was 0.2 ng, and the minimum detectable concentration of thifensulfuron-methyl in the samples of soil, corn grains and plants were 2 μg/kg. The average recoveries ranged from 77. 9% - 100. 4% , with variation coefficient from 1.6 %- 6.5 %. The results of two-year field trial showed that the half-lives of thifensulfuron-methyl in soil were in a range of 0.92- 1.23 days. When the corn field was treated by thifensulfuron-methyl 75% WP at 33.3 g/hm^2- 50 g/hm^2 （a. i. 25 g/hm^2 -37.5 g/hm^2） one time at corn 2 - 3 leaf growth period, the residues in soil, corn grains and plants were less than 2 μg/kg at 40 or 80 days after application.