Multiresidue analysis of 36 pesticides in soil using a modified quick, easy, cheap, effective, rugged, and safe method by liquid chromatography with tandem quadruple linear ion trap mass spectrometry

Prediction of the Impact of Land Use and Soil Type on Concentrations of Heavy Metals and Phthalates in Soil Based on Model Simulation

The main objective of this study is to determine the possibility of predicting the impact of land use and soil type on concentrations of heavy metals (HMs) and phthalates (PAEs) in soil based on an artificial neural network model (ANN). Qualitative analysis of HMs was performed with inductively coupled plasma-optical emission spectrometry (ICP/OES) and Direct Mercury Analyzer. Determination of PAEs was performed with gas chromatography (GC) coupled with a single quadrupole mass spectrometry (MS). An ANN, based on the Broyden-Fletcher-Goldfarb-Shanno (BFGS) iterative algorithm, for the prediction of HM and PAE concentrations, based on land use and soil type parameters, showed good prediction capabilities (the coefficient of determination (r²) values during the training cycle for HM concentration variables were 0.895, 0.927, 0.885, 0.813, 0.883, 0.917, 0.931, and 0.883, respectively, and for PAEs, the concentration variables were 0.950, 0.974, 0.958, 0.974, and 0.943, respectively). The results of this study indicate that HM and PAE concentrations, based on land use and soil type, can be predicted using ANN.

Chromatographic techniques for the analysis of organophosphate pesticides with their extraction approach: a review (2015-2020)

In agriculture, a wide range of OPPs has been employed to boost crop yield, quality, and storage life. However, due to the ever-increasing population and rapid urbanization, pesticide use has surged in recent years. These compounds are exceedingly poisonous to humans, and despite the fact that specific legislation prohibits their use, the frequency of toxic and/or fatal incidents, as well as current statistics, suggest that they are currently accessible. As a result, determining the exposure to these substances as well as their detection (and that of their metabolites) in different types of exposed samples has become a hot issue in terms of quality and safety concerns. However, developing tools for the evaluation of these substances is a critical challenge for laboratories. Various chromatographic-based methods reported in the period of 2015-2020 have been developed, which are summarized and critically reviewed in this article, including the extraction of the target OPPs from different kinds of matrices. A comparison among the extraction and analysis techniques has been made in the current review article.

Determination study of contaminants of emerging concern at trace levels in agricultural soil. A pilot study

In this study, we aimed to develop and validate a quick, easy, and robust extraction method for the simultaneous determination of 30 organic contaminants of emerging concern (CECs) including some transformation products in soil samples. Three different extraction methods based on an ultrasonic cylindrical probe (UAE), a pressurized liquid extraction (PLE), and a QuEChERS method were compared. Ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry (LC-MS/MS) was used for identification and quantification of the target analytes. A modified QuEChERS method showed the best results in terms of extractability and accuracy. The extraction procedure developed provided adequate extraction performances (70% of the target analytes were recovered within a 70-99% range), with good repeatability and reproducibility (variations below 20%) and great sensitivity (LOQ < 0.1 ng/g in most cases). No matrix effects were observed for 70% of the compounds. Finally, the analytical methodology was applied in a pilot study where agricultural soil was irrigated with reclaimed water spiked with the contaminants under study. Of the 25 CECs added in irrigation water, a total of 13 pesticides and 5 pharmaceutical products were detected at concentration ranges from 0.1 to 1.2 ng/g (d.w) and from 0.1 to 2.0 ng/g (d.w), respectively.

Residue, dissipation, and safety evaluation of etoxazole and pyridaben in Goji berry under open-field conditions in the China's Qinghai-Tibet Plateau

The dissipation and residual levels of etoxazole and pyridaben in Goji berry under open field conditions were determined by using GC-NPD (gas chromatography with nitrogen and phosphorus detector) with modified QuEChERS method. At fortification levels of 0.01, 1, and 5 mg/kg in Goji berry, it was shown that recoveries were ranged from 80.40 to 100.9% with relative standard deviation of the method (RSD) for repeatability ranged from 2.20 to 4.25%. The limit of quantification (LOQ) of the method was 0.01 mg/kg. The dissipation rates of etoxazole and pyridaben were described by using first-order kinetics and its half-life, as they are 7.13 days, 5.77 days, and 5.99 days (etoxazole) and 1.02 day, 0.67 day, 1.02 day (pyridaben). The terminal residues of etoxazole and pyridaben were below the European maximum residue limit (MRL, 0.1 mg/kg) in Goji berry when measured 7 days after the final application, which suggested that the use of these insecticides was safe for humans. This study would help in providing the basic information for developing regulation to guard a safe use of etoxazole and pyridaben in Goji berry and prevent health problem from consumers.

Currently and recently used pesticides in Central European arable soils

Although large amounts of pesticides are used annually and a majority enters the soil to form short- or long-term residues, extensive soil surveys for currently used pesticides (CUPs) are scarce. To determine the status of CUPs' occurrence in arable land in Central Europe, 51 CUPs and 9 transformation products (TPs) were analysed in 75 arable soils in the Czech Republic (CR) several months after the last pesticide application. Moreover, two banned triazines (simazine and atrazine) and their TPs were analysed because of their frequent detection in CR waters. Multi-residue pesticide analysis on LC-MS/MS after soil QuEChERS extraction was used. The soils contained multiple pesticide residues frequently (e.g. 51% soils with ≥5 pesticides). The levels were also noticeable (e.g. 36% soils with ≥3 pesticides exceeding the threshold of 0.01mg/kg). After triazine herbicides (89% soils), conazole fungicides showed the second most frequent occurrence (73% soils) and also high levels (53% soils with total conazoles above 0.01mg/kg). Frequent occurrence was found also for chloroacetanilide TPs (25% of soils), fenpropidin (20%) and diflufenican (17%). With the exception of triazines' negative correlation to soil pH, no clear relationships were found between pesticide occurrence and soil properties. Association of simazine TPs with terbuthylazine and its target crops proved the frequent residues of this banned compound originate from terbuthylazine impurities. In contrast, frequent atrazine-2-hydroxy residue is probably a legacy of high atrazine usage in the past. The occurrence and levels of compounds were closely associated with their solubility, hydrophobicity and half-life. The results showed links to CR water-monitoring findings. This study represents the first extensive survey of multiple pesticide residues in Central European arable soils, including an insight into their relationships to site and pesticide properties.

Simultaneous determination of three organophosphorus pesticides in different food commodities by gas chromatography with mass spectrometry

A sensitive and selective gas chromatography with mass spectrometry method was developed for the simultaneous determination of three organophosphorus pesticides, namely, chlorpyrifos, malathion, and diazinon in three different food commodities (milk, apples, and drinking water) employing solid-phase extraction for sample pretreatment. Pesticide extraction from different sample matrices was carried out on Chromabond C18 cartridges using 3.0 mL of methanol and 3.0 mL of a mixture of dichloromethane/acetonitrile (1:1 v/v) as the eluting solvent. Analysis was carried out by gas chromatography coupled with mass spectrometry using selected-ion monitoring mode. Good linear relationships were obtained in the range of 0.1-50 μg/L for chlorpyrifos, and 0.05-50 μg/L for both malathion and diazinon pesticides. Good repeatability and recoveries were obtained in the range of 78.54-86.73% for three pesticides under the optimized experimental conditions. The limit of detection ranged from 0.02 to 0.03 μg/L, and the limit of quantification ranged from 0.05 to 0.1 μg/L for all three pesticides. Finally, the developed method was successfully applied for the determination of three targeted pesticides in milk, apples, and drinking water samples each in triplicate. No pesticide was found in apple and milk samples, but chlorpyrifos was found in one drinking water sample below the quantification level.

Dissipation behavior of phorate and its toxic metabolites in the sandy clay loam soil of a tropical sugarcane ecosystem using a single-step sample preparation method and GC-MS

The dissipation of phorate in the sandy clay loam soil of tropical sugarcane ecosystem was studied by employing a single-step sample preparation method and gas chromatography with mass spectrometry. The limit of quantification of the method was 0.01 μg/g. The recoveries of phorate, phorate sulfoxide, phorate sulfone, and phorate oxon were in the range 94.00-98.46% with relative standard deviations of 1.51-3.56% at three levels of fortification between 0.01 and 0.1 μg/g. The Half-life of phorate and the total residues, which include phorate, phorate sulfoxide and phorate sulfone, was 5.5 and 19.8 days, respectively at the recommended dose of insecticide. Phorate rapidly oxidized into its sulfoxide metabolite in the sandy clay loam soil. Phorate sulfoxide alone accounted for more than 20% of the total residues within 2 h post-application and it was more than 50% on the fifth day after treatment irrespective of the doses applied. Phorate sulfoxide and phorate sulfone reached below the detectable level on 105 and 135 days after treatment, respectively as against 45 days after treatment for phorate residues at the recommended dose. Thus, the reasonably prolonged efficacy of phorate against soil pests may be attributed to longer persistence of its more toxic sulfoxide and sulfone metabolites.