Ultrasound-assisted QuEChERS-based extraction using EDTA for determination of currently-used pesticides at trace levels in soil

Abstract

It is essential to monitor pesticides in soils as their presence at trace levels and their bioavailability can induce adverse effects on soil's ecosystems, animals, and human health. In this study, we developed an analytical method for the quantification of traces of multi-class pesticides in soil using liquid chromatography-tandem mass spectrometry. In this way, 31 pesticides were selected, including 12 herbicides, 9 insecticides, and 10 fungicides.Two extraction techniques were first evaluated namely: the pressurized liquid extraction and the QuEChERS procedure. The latest one was finally selected and optimized, allowing extraction recoveries of 55 to 118 %. The addition of the chelating agent EDTA, which binds preferentially to soil cations that complex some pesticides, facilitates their extraction. Coupled with liquid chromatography-tandem mass spectrometry, the procedure displayed very high sensitivity, with limits of quantification (LOQ) in the range 0.01-5.5 ng/g. A good linearity (R² >0.992) was observed over two orders of magnitude (LOQ-100×LOQ) with good accuracy (80% -120 %) for all compounds except the two pyrethroids lambda-cyhalothrin and tau-fluvalinate (accuracy comprised between 50 and 175%) and the cyclohexanedione cycloxydim (accuracy<35%). Good repeatability and reproducibility were also achieved. The method was finally successfully applied to 12 soil samples collected from 3 land-use types. Among the 31-targeted pesticides, 24 were detected at least once, with concentration levels varying from LOQ to 722 ng/g. Many values were below 0.5 ng/g, indicating that the developed method could provide new knowledge on the extremely low residual contents of some pesticides.

Pesticide-Residue Analysis in Soils by the QuEChERS Method: A Review

“…The analytical performance of the QuEChERS method for the analysis of pesticide residues in soils has been compared with other extraction methods, such as accelerated solvent extraction (ASE) [20,29], MAE [29], PLE [14,21,27,51,55], solid-liquid extraction (SLE) [21,44], Soxhlet extraction [44], and USE [14,21,29,51]. Although ASE, MAE, and USE were developed as more practical, faster, and more environmentally friendly procedures than the Soxhlet method, the QuEChERS method has since become the first choice of analytical chemists due to its high-throughput performance and easy modification according to the analytical needs of specific combinations of analytes and matrices.…”

“…Consequently, the type and amount of cleaning sorbent have been the factors that have received the most attention for these applications. In this regard, a considerable number of studies have been published on the combination of MgSO 4 and/or PSA with other common sorbents, such as octadecylsilane (C 18 ) [23,24,27,28,31,34,44,51,55] and/or graphitized carbon black (GCB) [41,43,57]. On one hand, since C 18 is a reversed-phase sorbent which has been particularly effective at removing nonpolar interferences from fatty extracts [4], it would be very useful to clean extracts from soils with high organic matter.…”

Validation of the Chemical and Biological Steps Required Implementing an Advanced Multi-Omics Approach for Assessing the Fate and Impact of Contaminants in Lagoon Sediments

“…Semi targeted analytical methodologies were developed for the analysis of both water and sediment matrices from "Canet-St Nazaire" lagoon. These developments were carried out based on previous works performed in the Analytical Sciences Institute (ISA, Villeurbanne, France) [27,28]. Rigorous sample preparations were set up in order to obtain reproducible and sensitive analytical methods.…”

“…Two solid/liquid extraction methods were firstly evaluated: the QuEChERS method and an extraction based on the use of the mix acetonitrile/methanol (50/50). The QuEChERS extraction, based on the use of acetonitrile, was chosen because it is really easy and fast to set up and often used for environmental matrix [28][29][30][31][32][33][34][35][36][37][38]. In parallel, a mixture of acetonitrile and methanol as extraction solvent was also evaluated in an attempt to extend the polarity range of the extracted metabolites.…”