基质固相分散萃取－高效液相色谱串联质谱法测定土壤中残留的磺酰脲类除草剂

摘要

建立了基质固相分散萃取－高效液相色谱串联质谱法( MSPD－HPLC－MS/MS)测定土壤中3种磺酰脲类除草剂(氯磺隆、甲磺隆、苯磺隆)残留的分析方法。对基于球磨的基质固相分散萃取条件进行了详细优化,最终确定最佳条件为：0.2 g土壤样品、0.8 g HC－C18粉末状分散剂与直径为8 mm的小钢珠一起球磨10 min后,转移至空的玻璃萃取小柱,用10 mL乙腈洗脱,氮气吹干后用甲醇定容至0.6 mL,再经0.22μm的滤膜抽滤后装入自动进样瓶中。用Syncronis C18反相色谱柱分离,以甲醇( A)~1‰甲酸溶液( B)为流动相进行梯度洗脱,选择反应监测( SRM)模式下进行检测。氯磺隆在20~200μg•kg－1,甲磺隆和苯磺隆在10~200μg•kg－1范围内线性良好,相关系数r在0.9979~0.9995。土壤样品的平均加标回收率在84.7％~104.6％,相对标准偏差在4.5％~7.9％(n＝5)。方法的检出限(S/N＝3)0.32~0.68μg•kg－1。该方法简单、效率高、干扰少、回收率高,满足土壤中除草剂的残留分析要求。%An analytical method for the simultaneous determination of 3 sulfonylurea herbicides ( Chloride methyl, Methyl methyl, Tribenuron ) was established by matrix solid-phase dispersion extraction ( MSPD) with high performance liquid chromatography tandem mass spectrometry ( HPLC-MS/MS) . Based on ball milling of sample pretreatment of MSPD, the extraction conditions were optimized in detail as following: grinded about 0. 2 g soil sample and 0. 8 g HC-C18 solid phase ex-traction powder with 8 mm small steel ball for 10 min and then loaded into the empty glass extraction column. The mixture was eluted with 10 mL of acetone, and concentrated to 0. 6 mL with methanol, then choulved by the 0. 22 μm membrane and then transfered to the automatic sample bottle. The 3 sulfonylurea herbicides were separated upon a Syncronis C18 col-umn using methanol ( A) ~1‰formic acid solution ( B) as mobile phase by gradient elution, and detected by MS under selected reaction monitoring ( SRM) mode. The results indicated that the Chlorsulfuron achieved the good linearities in the range of 20~200 μg•kg -1 , and the other two sulfonylurea herbicides achieved the good linearities in the range of 10~200 μg•kg -1 , with correlation coefficients from 0. 997 9 ~0. 999 5. The recoveries at three spiked levels were ranged from 84. 7% ~104. 6% and RSDs were 4. 5% ~7. 9%. The limits of detection ( LODs) for the target compounds ranged from 0. 32~0. 68 μg•kg-1 . The suggested method was simple, efficient, and less interference with high recovery rate, and met the analytical requirements of herbicide residues in soil.