大豆中硝磺草酮的残留量测定

摘要

A novel QuEChERS method was developed for the rapid determination of mesotrione residue in soybean using high performance liquid chromatography tandem-mass spectrometry ( HPLC–MS/MS) . The samples were extracted with acetonitrile, then salted out with NaCl, purified with GCB and Cl8, separated on a phenomenex Luna 3u C18 (2) 100A column with gradient elution by using acetonitrile and 0.1% ammonia aqueous as eluant, and detected by HPLC–MS/MS under negative electrospray ionization ( ESI–) and multiple-reaction monitoring ( MRM) models. Under these condi﹣tions, mesotrione showed a good linear relationship ( R 2>0.997) in the concentration range of 0.0075–0.75 μg/mL, and the limit of quantification (LOQ) and limit of detection (LOD) in soybean were 0.003 and 0.0009 mg/kg, respec﹣tively. Three spiked levels at 0.003, 0.03 and 0.3 mg/kg were investigated, and the intra-day average recoveries ranged from 83.84% to 96.24%, with intra-day relative standard deviations ( RSDs) of 1.99-3.78%, the inter-day average re﹣coveries ranged from 85.13% to 95.25%,inter-day RSDs of 2.11-3.47%, which met the requirement of mesotrione de﹣termination in soybean.%为快速检测大豆中硝磺草酮残留量建立了高效液相色谱–串联质谱的新方法。大豆样品采用乙腈提取， NaCl盐析，十八(烷)基硅烷(C18)和石墨化炭黑(GCB)分散固相萃取净化，以phenomenex Luna 3u C18(2)100A柱为分离柱，用乙腈和0.1％氨水溶液进行梯度洗脱，电喷雾负离子( ESI–)多反应监测，高效液相色谱–串联质谱( HPLC–MS/MS)测定。本方法条件下，硝磺草酮在0.0075–0.75μg/mL浓度范围内呈良好的线性关系(R2>0.997)，方法检出限(LOD)和定量限(LOQ)分别为0.0009和0.003 mg/kg。在0.003、0.03和0.3 mg/kg添加水平下，硝磺草酮的日内平均回收率为83.84–96.24％，日内相对标准偏差( RSD)为1.99–3.78％，日间平均回收率为85.13–95.25％，日间RSD为2.11–3.47％，能满足大豆中硝磺草酮检测的要求。