气相色谱-串联质谱法快速测定水中五种除草剂

Stimultaneous Determination of Five Herbicides in Water With Gas Chro matography-tandem Mass Spectrometry

目的建立气相色谱-串联质谱法快速测定水中5种除草剂。方法水样采集后,采用石油醚分次萃取,合并萃取液旋转蒸发后用丙酮定容,气相色谱-串联质谱直接测定,根据保留时间定性,标准曲线法定量。结果水中5种除草剂在0.02-1.0 mg/L范围内具有良好的线性,相关系数均≥0.999。对于500 ml水样,本方法的检出限分别为甲草胺0.01μg/L、乙草胺0.01μg/L、丁草胺0.02μg/L、莠去津0.01μg/L、扑草净0.01μg/L。5种除草剂测定的日内精密度为1.6%-7.0%,日间精密度为2.7%-6.9%;加标回收率分别为甲草胺81.7%-85.6%,乙草胺87.4%-95.4%,丁草胺87.7%-91.2%,莠去津84.5%-92.3%,扑草净86.2%-92.5%。结论建立了同时快速测定水中五种除草剂的气相色谱-串联质谱法,具有操作简单、快速、选择性好、准确度高等特点,适用于同类别除草剂污染水体的大量样品的快速筛查和测定。

Objective To develop a method for simultaneously determination of five herbicides by using Gas chro matography- tandem mass spectrometry（ GC- MS）. Methods Water was extracted with petroleum ether and concentrated by rotary evaporator. The samples were injected into GC-MS after constant volu-me with acetone and were determined for qualitative analysis with retention time and quantitative analysis with standard curve method. Results Under the optimal conditions,good linearity（ r≥0. 999） was observed in the range of 0. 02-1. 0 mg / L of the target compounds. For the 500 ml samples,the detection li-mit of herbicides was 0. 02 mg / L for butachlor and 0. 01 mg / L for others. The inter-day and intra- day precisions ranged from 1. 6- 7. 0% and2. 7-6. 9% respectively. The spiked recovery of alachlor,acetochlor,butachlor,atrazine and prometryne in water sample were in the range of 81. 7- 85. 6%,87. 4- 95. 4%,87. 7- 91. 2%,84. 5- 92. 3% and 86. 2-92. 5%,respectively. Conclusion The method for si-multaneous deter mination of five herbicides in water by GC-MS is established and the advantages of si-mple operation,fast,good selectivity and high accuracy,rapid screening are showed. It is applicable to deter minate for a large nu mber of sa mples.