Development and validation of a GC × GC-ToFMS method for the quantification of pesticides in environmental waters

Abstract

Water is a fundamental resource for living things, which is why its control is necessary. The widespread use of pesticides for agricultural and non-agricultural purposes has resulted in the presence of their residues in surface water and groundwater resources. Their presence in water is regulated through different directives, such as the Groundwater Directive, the Drinking Water Directive, and the Water Framework Directive, modified later several times, setting a maximum concentration of 0.1 µg.L−1 for individual pesticides and their degradation products, and 0.5 µg.L−1 for total pesticide residues present in a sample. There are different kinds of pesticides (e.g., organophosphorus and organochlorine pesticides, triazines, chloroacetamides, triazoles, (thio)carbamates) that have diverse chemical structures. Their determination and monitoring in a single analytical procedure are possible through multiresidue methods. In this study, 53 pesticides belonging to different chemical classes and their metabolites were selected based on their local occurrence and investigated in surface water and groundwater from agricultural areas susceptible to pesticide contamination. The methodology consisted of a classical solid-phase extraction (SPE) for the purification and enrichment of the pesticides, with a subsequent analysis in multidimensional gas chromatography coupled to mass spectrometry (GC×GC-MS). The quantification method was validated according to the Eurachem Guide in terms of linearity, precision, accuracy, limit of detection, and limit of quantification. After validation, the method was applied to 34 real-world water samples, and the results were compared with those obtained by a GC-QMS routine method.

Acidified QuEChERS method followed by GC-MS/MS on-cold injection for the determination of captan and folpet metabolites in strawberries and apple

“…In this study, the method performance characteristics were evaluated from the validation results following the EC guidelines [20,21] . The method was validated by evaluating the detection's linearity and limit, boundary of quantification, trueness, robustness, precision, and uncertainty.…”

“…As soon as the matrix's lowest concentration of the target analytes was acceptable with appropriate accuracy and precision was found discovered, LOQs were set up [20] . Table 2 summarizes the repeatability results of validation that applied on both apple and strawberries.…”

“…One more detection approach for captan and folpet's simultaneous determination utilizing GC equipped with negative chemical ionization-mass spectrometry (GC-NCI-MS) and two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-ToFMS) with linear concentration ranged from 50 to 2500µg/L at 50µg/kg [19,20] . Most of the previously mentioned quantitative determination techniques used more steps to stabilize captan and folpet form degradation or hydrolysis in all stages that increase both time and cost of analysis.…”

Integrating Wireless Remote Sensing and Sensors for Monitoring Pesticide Pollution in Surface and Groundwater

“…The popularity of instrumental techniques in the detection of pesticides in water lies in their superiority in performing trace analysis in complex matrices [41]. Very low limits of detection (LOD) and limits of quantification (LOQ) are achieved when these techniques are coupled with tandem mass spectrometry (MS/MS), a procedure commonly applied while screening a wide variety of unknown contaminants in non-target analysis [42,43]. A study carried out in France applying online solid phase extraction ultra-power liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) to herbicides and pharmaceutical compounds identified 15 emerging micropollutants in water at low detection and quantification limits averaging 10 ng per litre and 30 ng per litre, respectively [44].…”

Investigative Approaches for Pollutants in Water: Aligning with Water Framework Directive Maximum Allowable Concentrations

“…GC×GC techniques have gained increasing popularity in analyzing complex samples [88,130]. In contrast to conventional GC, GC×GC offers improved peak capacities, yields a more distinct and comprehensive chromatogram, enhances resolution, and improves the capability for group-type analysis.…”