气相色谱-质谱法测定渔业水质中8种除草剂的残留量

摘要

To measure herbicides residues in fishery water, gas chromatography-mass spectrometry was developed to determine trifluralin, pendimethalin, alachlor, acetochlor, butachlor, simazine, atrazine, and prometryn. The samples were adjusted to salinity 20−30 with NaCl, extracted by dichloromethane, and cleaned up with Florisil solid phase extraction (SPE) column. The analytes were detected by gas chromatography-mass spectrometry under the selected reaction monitoring mode and quantified by external standard method. The peak area was linear to the concentration of eight herbicides residues (0.010−1.000 µg/L), and the correlation coefficients (R2) were all more than 0.990. According to S/N≥3, the detection limit of rifluralin, simazine, atrazine, acetochlor, alachlor, prometryn, pendimethalin, and butachlo were 0.022, 0.031, 0.028, 0.038, 0.041, 0.035, 0.025, and 0.020 μg/L, respectivly. The limit of quantification was 0.05 μg/L for all eight herbicides based on the actual samples spiked recoveries between 70% and 120%, S/N≥10, and the relative standard deviation≤15%. The average recovery of the eight herbicides fortified in different negative samples at 0.05, 0.5, and 2.0 µg/L were in the range of 74.7%−97.7%, and the relative standard deviations were less than 12.00%. These results indicated that the method has the advantage of simplicity, sensitivity and repeatability, which could provide technical support for the detection of these eight herbicides residues in fishery water.%本研究建立了测定渔业水质中氟乐灵、二甲戊灵、甲草胺、乙草胺、丁草胺、西玛津、莠去津、扑草净8种除草剂残留量的气相色谱-质谱法。样品用氯化钠调节盐度至20−30，二氯甲烷提取，无水硫酸钠除水，过弗罗里硅土固相萃取小柱净化，利用气相色谱-质谱法，以选择离子监测模式检测，外标法进行定量分析。采用基质匹配标准溶液校准法，8种除草剂在0.010−1.000µg/L范围内线性良好，R2均大于0.990；方法检出限以信噪比≥3估算，检出限分别为：氟乐灵0.022µg/L、西玛津0.031µg/L、莠去津0.028µg/L、乙草胺0.038µg/L、甲草胺0.041µg/L、扑草净0.035µg/L、二甲戊灵0.025µg/L、丁草胺0.020µg/L。选择0.05、0.5和2.0µg/L 3个不同浓度水平做加标回收，平均回收率为74.7%−97.7%，相对标准偏差在12.0%以内。方法检出限分别为：氟乐灵0.022µg/L、西玛津0.031µg/L、莠去津0.028µg/L、乙草胺0.038µg/L、甲草胺0.041µg/L、扑草净0.035µg/L、二甲戊灵0.025µg/L、丁草胺0.020µg/L，最低定量限均为0.05µg/L。该方法具有操作简便、准确性好、灵敏度高、重现性好等优点，可为渔业水质中这8种除草剂残留的监测提供技术支持。