分散液液微萃取/超高效液相色谱-串联质谱法测定环境水中7种新烟碱类农药

Determination of 7 Neonicotinoid Pesticides in Environmental Water by Dispersion Liquid-Liquid Microextraction Combined with UPLC-MS/MS

建立了巴氏滴管辅助的分散液液微萃取(PTD-DLLME)结合超高效液相色谱-串联质谱(UPLC-MS/MS)同时测定环境水中7种新烟碱类农药的方法。该方法首次以巴氏滴管作为萃取容器,低密度低毒性的乙腈作为萃取剂,丙酮为分散剂。采用BEH C_(18)(2.1 mm×50 mm,1.7μm)色谱柱分离,0.01%甲酸水溶液(含2 mmol/L甲酸铵)和0.01%甲酸乙腈溶液(含2 mmol/L甲酸铵)为流动相梯度洗脱,电喷雾离子源(ESI)正离子方式扫描,多反应监测(MRM)模式监测,以保留时间和特征离子定性,外标法定量。在最优实验条件下,目标化合物在0.05~100μg/L范围内线性关系良好,相关系数(r2)不低于0.996,检出限(LOD)为0.02~0.1μg/L,定量下限(LOQ)为0.05~0.2μg/L,富集倍数为10倍。在1倍、2倍和10倍LOQ 3个加标水平下,各待测物的回收率为75.3%~116%,日内相对标准偏差(Intra-RSD,n=6)为2.7%~8.2%,日间相对标准偏差(Inter-RSD,n=3)为3.1%~10%,基质效应为-0.18%~6.66%。采用该方法对20批环境水样进行检测,其中1批河水样品中检出吡虫啉与噻虫啉,其浓度低于LOQ。该方法具有便于操作、富集效果好、回收率稳定、绿色环保以及成本低廉的优点,为环境水样中新烟碱类农药的检测提供了一种全新的解决方案。

The dispersion liquid-liquid microextraction assisted by pasteurized dropper(PTDDLLME)combined with ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)method was established for the simultaneous determination of 7 neonicotinoid pesticides in environmental water.In the experiment,a pasteurized dropper was used as the extractor,acetonitrile with low density and low toxicity was used as the extractant,and acetone was used as the dispersant for the first time.The separation was performed on a BEH C_(18) column(2.1 mm×50 mm,1.7μm)by gradient elution,with 0.01%formic acid aqueous solution(containing 2 mmol/L ammonium formate)and 0.01%formic acid acetonitrile solution(containing 2 mmol/L ammonium formate)as the mobile phases.After optimization of the gradient elution procedures and mass spectrometric conditions,chromatographic separation and feature recognition of the 7 neonicotinoid pesticides were obtained.Moreover,the optimal extraction conditions were determined as follows:sampling volume was 10 mL,extraction salt was 1 g NaCl and 4 g MgSO4,extractant was acetonitrile(800μL),and dispersant was acetone(400μL),which was confirmed by the best extraction efficiency in the sample pretreatment.Analytes were scanned in positive ion mode by electrospray ionization source(ESI)under multiple reaction monitoring(MRM)mode,qualitated by retention time and characteristic ion,and quantitated by external standard method.Under the optimal conditions,the linear relationship of target compounds were good in the range of 0.05-100μg/L with the correlation coefficients(r2)not less than 0.996.The limits of detection(LOD)were in the range of 0.02-0.1μg/L,while the limits of quantitation(LOQ)were in the range of 0.05-0.2μg/L,and the enrichment ratio was 10 times.At the spiked levels of 1,2 and 10 times LOQ,the recoveries of the analytes ranged from 75.3%to116%,and the relative standard deviations of intraday(Intra-RSDs,n=6)were 2.7%-8.2%and that of interday(Inter-RSDs,n=3)were 3.1%-10%.The matrix effects of the 7 neonicotinoid pesticides ranged from-0.18%to 6.66%.The established method was applied to 20 batches of environmental water samples,in which imidacloprid and thiacloprid were detected in one river water sample,but their concentrations were below LOQ.This study indicated that PTD-DLLME combined with UPLC-MS/MS is an effective analytical method to detect 7 neonicotinoid pesticides in environmental water.The method is easy to operate,has a good enrichment effect,and offers stable recovery,environment friendly,and low cost,providing a new solution for the detection of neonicotinoid pesticides in environmental water samples.