Validation and Application of a Multi-residue Method, Using Accelerated Solvent Extraction Followed by Gas Chromatography, for Pesticides Quantification in Soil

Abstract

A multi-residue method was developed to determine different types of pesticides in soils. An extraction with pressure and temperature, through accelerated solvent extraction (dichloromethane:acetone, 50:50, v/v). The pesticides were determined by gas chromatography with several selective detectors: electron capture detector, pulsed flame photometric detector and thermionic specific detector. The following parameters were determined: limit of detection, limit of quantification, equipment linearity (working interval), method linearity as well as, method accuracy and precision. The average recoveries ranged between 76 and 106%, with the exception of chlorothalonil, which had an average recovery of 46%. Additionally, detection limits from 0.9 to 7.6ng g -: (1) and the quantification limits from 3.00 to 25.47ng g -: (1) were estimated. In terms of linearity and precision, the results obtained were in the ranges considered adequate (R(2) ≥ 0.98 and coefficient of variation (CV) ≤ 20%), with the exception of aldrin (R(2) = 0.946, CV = 35.79%), lindane (R(2) = 0.917, CV = 32.91%) and chlorothalonil (R(2) = 0.8184, CV = 81.35%). The proposed method was used to evaluate pesticides in real soil samples, detecting concentrations over 1000ng g -: (1) for some pesticides. The method was correctly validated and provided for the rapid determination of pesticides in soil.

Sample Preparation Methods for Pesticide Analysis in Food Commodities, Biological and Environment Matrices

“…Solid matrices including soil, sediment, food commodities, and air sampling solid sorbent materials (filter, polyurethane foam, solid sorbents (XAD-2, XAD-4, Tenax-TA)) are extracted prior to an SPE (or dSPE) cleanup step with a variety of approaches including microwave extraction, pressurized liquid extraction (as referred commonly as pressurized solvent extraction), ultrasonic extraction, and traditional solid-liquid extractions [41,45,57,61,66,[78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96]. These approaches are not selective and the polarity of the organic solvents and choices of additives in these extraction procedures will impact the co-extractive matrix, which necessitate the subsequent SPE or dSPE cleanup choices.…”

“…In addition, for SPE, aqueous extracts are easier to optimize SPE loading, washing, and elution steps as extracts of organic solvents need careful consideration to ensure adequate retention of target analytes on sorbent materials to prevent washout. The most common solvent choices for pressurized liquid extraction and microwave extraction of solid matrices were acetonitrile, ethyl acetate, acetone, hexane, or combinations of these solvents [81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96]. With microwave extraction, acetone has been added to hexane (2:1) to improve the recoveries for polar OPs, while use of hexane can reduce matrix co-extractives [81].…”

“…Reduction in coextracts has also been reported with acetonitrile rather than methanol or acetone (with microwave extraction) and good recoveries have been reported for OCs and neonicotinoids [83,84]. Hexane, dichloromethane, ethyl acetate, acetone, and acetonitrile have also been commonly used for pressurized solvent extraction of a large range of polarity of pesticides [41,57,65,66,[85][86][87][88][89][90][91][92][93][94][95][96].…”

A simple and economical method of gas chromatography-mass spectrometry to determine the presence of 6 pesticides in human plasma and its clinical application in patients with acute poisoning

“…In cases of acute poisoning, determining the presence of a pesticide in human blood can provide information to identify the type of pesticide, the absorbed dose, and the degree of exposure to target tissues prior to elimination from the body (7,8). The volatility, thermal stability, and low polarity of pesticides render them suitable for gas chromatographic analysis, and particularly for the determination of their presence in biological matrices (9). Gas chromatography coupled with mass spectrometry (GC-MS or GC-MS/MS), which can avoid most matrix interference, has been used when a highly selective detection is required (10,11).…”

DISEÑO DE EXPERIMENTOS APLICADO EN LA OPTIMIZACIÓN DEL MÉTODO DE EXTRACCIÓN QuEChERS PARA LA DETERMINACIÓN DE PLAGUICIDAS ORGANOCLORADOS Y ORGANOFOSFORADOS EN SUELOS

“…Algunos ejemplos que implican este tipo de extracción son: la extracción por Soxhlet, la agitación, la extracción acelerada con disolventes (ASE, por sus siglas en inglés) y la extracción ultrasónica asistida (UAE, por sus siglas en inglés) (Tor et al 2006, Lesueur et al 2008, Djurovic et al 2012, Tadeo et al 2012, Ahmadi et al 2015, Leyva-Morales et al 2015. En cuanto a los métodos modernos, la extracción asistida por microondas (MAE, por sus siglas en ingles), la extracción con líquido presurizado (PLE, por sus siglas en ingles), la microextracción en fase sólida (SPME, por sus siglas en ingles) y la extracción "rápida, fácil, económica, efectiva, robusta y segura" (QuEChERS, por sus siglas en inglés) han mostrado ser los que requieren menor tiempo de extracción y bajo consumo de solventes (Bouaid et al 2001, Lesueur et al 2008, Vega et al 2008, Correia-Sá et al 2012, Tadeo et al 2012, Vera et al 2013, Masiá et al 2015.…”