全二维气相色谱-电子捕获检测器测定复杂基质土壤中24种有机氯和拟除虫菊酯类农药

时磊; 孙艳艳; 沈小明; 吕爱娟; 蔡小虎; 刘娇; 沈加林

doi:10.15898/j.cnki.11-2131/td.201906090082

全二维气相色谱-电子捕获检测器测定复杂基质土壤中24种有机氯和拟除虫菊酯类农药

Determination of 24 Organochlorine Pesticides and Pyrethroids in Complex Matrix Soils by Comprehensive Two-dimensional Gas Chromatography with Micro-electron Capture Detector

摘要

摘要: 目前针对环境样品中有机氯和拟除虫菊酯类农药的检测方法主要有气相色谱法和气相色谱-质谱法（GC-MS），由于气相色谱法采用电子捕获检测器从而具有较高的灵敏度，在污染物的环境行为研究中得到广泛应用，GC-MS法的定性效果好，但检测灵敏度相对偏低。本文研究了2018年土壤详查江苏地区样品中有机氯农药和拟除虫菊酯的残留状况，结果显示，即使经过多次净化仍有20%的样品存在假阳性或基质干扰现象。为了提高定性准确度，同时保证检测灵敏度，实验建立了复杂基质土壤中20种有机氯农药和4种拟除虫菊酯的全二维气相色谱-电子捕获检测器检测方法，最终选择中等极性的TG-35MS为第一色谱柱，非极性的（DB-1）为第二色谱柱，将鲜样与无水硫酸钠混合均匀后，以正己烷-丙酮（1：1，V/V）为提取剂进行索氏提取，采用全二维气相色谱-电子捕获检测器进行检测，外标法定量。各物质的质量浓度均在1.0~500μg/L内与其峰面积呈线性关系，相关系数均大于0.995，检出限为0.02~0.17μg/kg。用标准加入法进行回收实验，测得回收率为80.7%~103.5%，测定值的相对标准偏差（n=6）为1.84%~10.12%。本方法将高灵敏度检测器与全二维色谱相结合，在保证检测灵敏度的同时增加了峰容量，有效去除了基质干扰。相比2018年土壤详查参考方法HJ 835—2017的检出限0.02~0.09mg/kg（全扫模式），本方法检出限显著降低，且操作简单，可为复杂基质样品中的痕量超痕量检测提供参考。

Abstract:
BACKGROUNDCurrently the analysis methods of organochlorine pesticides and pyrethroids in environment samples are gas chromatography and gas chromatography-mass spectrometry (GC-MS). Gas chromatography with electron capture detector has been widely used in the study of environmental behavior of pollutants due to its high sensitivity. GC-MS has good qualitative results, but the detection sensitivity is relatively low.
OBJECTIVESTo establish an easy, highly efficient and precise method for determination of 20 organochlorine pesticides and 4 pyrethroids in complicated matrix soils.
METHODSThe residues of organochlorine pesticides and pyrethroids in samples from Jiangsu Province in 2018 were studied. In order to improve the qualitative accuracy and ensure the detection sensitivity, a comprehensive two-dimensional gas chromatography-electron capture detector detection method for determination of 20 organochlorine pesticides and 4 pyrethroids in complex-matrix soils was established. TG-35MS column (30m×0.25mm×0.25μm) was chosen as the column for the first dimension, and a DB-1 column (0.8m×0.18mm×0.18μm) was chosen as the column for the second dimension. The fresh sample was mixed with anhydrous sodium sulfate and extracted with hexane-acetone (1:1, V/V), subsequently purified by activated sheet copper. The analysis was conducted by GC×GC-μECD, qualified by retention time and quantified by external standard.
RESULTSThe proposed method showed good linearity with correlation coefficients (r) higher than 0.995 in the concentration range of 1.0-500μg/L, with the detection limits of 0.02-0.17μg/kg. The recovery of standard addition method ranged from 80.7% to 103.5%, and the relative standard deviations (n=6) were 1.84%-10.12%.
CONCLUSIONSThe proposed method combined high sensitivity detector with comprehensive two-dimension gas chromatography overcomes the matrix interference in complex sample, which shows a good detection sensitivity and peak capacity. The detection limit of the method is far lower than that of HJ 835-2017 standard (0.02-0.09). This method can provide reference for the analysis of multiple organochlorine pesticides and pyrethroids in complex-matrix soil.

HTML全文

参考文献(33)

施引文献

资源附件(0)