QuEChERS-高效液相色谱-串联质谱法测定粮谷中啶磺草胺的残留

Determination of pyroxsulam in the grain crops by QuEChERS-high performance liquid chromatography-tandem mass spectrometry

目的建立高效液相色谱-串联质谱法测定粮谷中啶磺草胺的分析方法。方法样品经酸化乙腈[含0.5%(V/V)乙酸的乙腈]提取,优化的QuEChERS(400 mg C18、400 mg无水硫酸镁)方法净化,净化液经离心后,直接过膜上机检测。高效液相色谱-串联质谱法以0.1%(V/V)甲酸水-乙腈为流动相,流速为0.3 mL/min梯度洗脱,采用C18色谱柱进行分离,电喷雾正离子电离,多反应监测检测,基质匹配外标法定量。结果在11种基质(大豆、大麦、大米、高粱、黑麦、苦荞、土壤、小麦粉、小麦、燕麦、玉米)中,啶磺草胺在0.001~0.03μg/mL质量浓度与其对应的峰面积之间线性关系良好,r^(2)均大于0.996,在0.005、0.01和0.05 mg/kg 3个添加水平下,啶磺草胺的平均回收率为90.3%~112.3%,相对标准偏差为1.1%~7.9%。结论该方法准确度、精密度和灵敏度均符合农药残留检测的要求。

Objective To establish an analytical method for the determination of pyroxsulam in grain by high performance liquid chromatography-tandem mass spectrometry.Methods The sample was extracted with acidic acetonitrile(containing 0.5%acetic acid),and purified by optimization of QuEChERS(400 mg C18,400 mg anhydrous magnesium sulfate)method,and then the extracting solution was centrifuged and filtrated before detection.The extract was separated in a C18 reversed-phase column with gradient elution of acetonitrile and 0.1%formic acid as the mobile phase,at a flow rate of 0.3 mL/min and detected in multiple reaction monitoring,matrix matching external standard method were applied for samples analysis.Results In 11 substrates(soybean,barley,rice,sorghum,rye,Tartary buckwheat,soil,wheat flour,wheat,oat,corn),the linear relationship between the concentration of pyroxsulam and its corresponding peak area was good at 0.001-0.03μg/mL.r^(2)were greater than 0.996.At 3 supplemental levels of 0.005,0.01 and 0.05 mg/kg,the average recoveries of pyroxsulam were 90.3%-112.3%,and the relative standard deviations were 1.1%-7.9%.Conclusion The accuracy,precision and sensitivity of this method are in line with the requirements of pesticide residue detection.