Analysis of 91 Pesticide Residues in Groundwater by Gas Chromatography-Mass Spectrometry

Abstract

BACKGROUND Fast screening of multiple pesticides in groundwater is an important technical support for comprehensively characterizing groundwater quality and ensuring groundwater safety. OBJECTIVES To establish a rapid, easy and highly efficient method for the determination of 91 pesticides in groundwater. METHODS By selecting and optimizing the water sample pretreatment method and gas chromatography-mass spectrometry analysis conditions, a rapid analysis method for the simultaneous determination of 91 pesticides in groundwater by gas chromatography-mass spectrometry (GC-MS) was established. The targets were determined by GC-MS and quantified by an internal standard. After optimization, the target substance adopts pulsed splitless injection, separated by Zebron Multiresidue-2 chromatographic column, and segmented selective ion scanning. RESULTS Under the optimized conditions, pesticides showed good linearity with the correlation coefficient between 0.9901 and 0.9997 in the concentration range of 1.0-1000μg/L. The water sample was subjected to liquid-liquid extraction and concentration of dichloromethane and then tested on the machine, yielding method detection limits (MDLs) of 3.1-12.5ng/L, the average recoveries of 54.3%-129%, and the relative standard deviation (RSD) of 1.2% to 20%. CONCLUSIONS Compared to previous studies, the method not only greatly improves the efficiency, reduces the cost of analysis, ensures the effectiveness of sample analysis, but also has wide applicability, high accuracy and high sensitivity. The method is more suitable for analysis of large batches of samples, which ensures the timeliness of sample analysis. The method has been successfully applied to the national groundwater pollution survey.

Keywords

• groundwater
• pesticide residues
• gas chromatography-mass spectrometry
• fast analysis