Determination Of Pesticides Research Articles

Advances in the application of ion chromatography-mass spectrometry in the fields of life and health

Ion chromatography is a technique commonly used to separate strongly polar and ionizable substances; it can be used to separate, identify, and quantify ionizable compounds in complex samples when coupled with mass spectrometry, and is currently being used in the application of food analysis, drug analysis, metabolomics and clinical poisoning analysis. Herein, we review the development of ion chromatography-mass spectrometry (IC-MS), its progress over the past 20 years, and future trends in the abovementioned areas. The IC-MS research progress and applications for the determination of inorganic anions, organic acids, polar pesticides, biogenic amines, and sugars in the food field are discussed. Drug analysis applications are discussed mainly in relation to the analysis of drug impurities, identifying drug degradation products, and determination of plasma concentration, while the separation and analysis of strongly polar metabolites, such as organic acids, sugar phosphates, and nucleotides in biological matrices are discussed in relation to metabolomics. Advances in the analysis of strongly polar or ionizable toxic compounds, such as alkyl methylphosphonic acid, methylphosphonic acid, glyphosate, 3-nitropropionic acid, and indandione rodenticides, are mainly discussed in clinical poisoning analysis field. This paper is expected to become a useful reference for the further expansion and application of IC-MS in the life and health fields.

Simultaneous determination of pesticides, mycotoxins and ferulic acid in Angelica sinensis by GC/LC-Q-TOF/MS

In this study, a strong applicable method that could determine a total of 33 pesticides (54 compounds), 11 mycotoxins and functional components (ferulic acid) simultaneously in Angelica sinensis was developed. The compatibility of the sample pretreatment method for pesticides, mycotoxins, and functional components was improved by optimizing the acidity of extraction solvents, the sequence of ice bath and oscillation, the volumetric solution, and so on. The PRiME HLB SPE pretreatment method was chosen as the optimal one when comparing four pretreatment methods. Among the 65 contaminants, 38 of those determined by liquid chromatography and 41 of those by gas chromatography, which showed good linearity (R2 > 0.9801), 97 % of them had a limit of quantitation (LOQ) of lower than 0.02 mg kg-1. The recovery of all compounds were suited between 70 % to 120 % and the RSD were all lower than 20 % at the spiked levels of LOQ, 2 × LOQ, and 10 × LOQ. For ferulic acid, the LOQ was 50 ng/mL, and it showed good linearity (R2=0.9988) within the range of 0.5 to 10 μg/mL. The recovery and RSD were 98.1 %, and 3.2 % (n = 6), respectively. The simultaneous determination of cross-category compounds in a single sample preparation was obtained by the combination of SPE and GC/LC-Q-TOF/MS. Therefore, this study could not only shorten the time for data acquisition and data analysis, but also improve the experimental efficiency.

The rapid detection of pesticide residues in fruits and vegetables using electrochemical methods

To meet global demand, pesticides play a very important role in the control of pests that damage agricultural products. However, overuse of pesticides threatens ecosystems and human health. In recent years, gas chromatography, liquid chromatography, gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, capillary chromatography and capillary electrophoresis have been used in the determination of pesticides. Although these methods are highly specific, highly selective and sensitive, the high value of sophisticated laboratory equipment and tools is a complex and time-consuming process. Because of this, electrochemical sensors and biosensor platforms have become good analytical methods for detecting pesticides due to a number of advantages, including ease of detection of system manufacturing processes, high sensitivity and selectivity. This article describes the methods of manufacturing portable electrochemical sensors for detecting pesticide residues in fruits and vegetables on site, that is, the achievements in recent years in the field of cyclic voltammetry, square wave voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy. In addition, detailed information is provided on the basic mechanism and electrochemical sensitivity of these methods. The development of electrochemical methods and real-time monitoring of smartphone technologies, as well as their integration with detection platforms, are discussed. For readers with a scientific and technological focus, this article will provide additional valuable information for understanding the creation of portable electrochemical devices, rapid detection of pesticides, the role of electrochemical sensitive methods and contributing to their further development.

Critical evaluation of high-resolution and low-resolution mass spectrometry for biomonitoring of human environmental exposure to pesticides

Despite increasing debates about their potential side effects on human health, data concerning the risks and the impacts associated with pesticides remains scarce. Analytical tools allowing the measurement of most pesticides and/or their metabolites to which the population can be exposed are also of need. In the present study, the limits of detection (LODs) of 3 different screening procedures based on either Low-Resolution and High-Resolution Mass Spectrometry (LR-MS and HR-MS) for the determination of pesticides in serum (among which carbamates, dithiocarbamates, neonicotinoids, organochlorines, organophosphates and pyrethroids) were explored. For HR-MS, a quadrupole time-of-flight was used in positive and negative electrospray ionization modes and data were obtained from either a targeted scheduled MSMS acquisition (HR-MSMS) or a data-independent acquisition (HR-DIA). For LR-MS, a triple quadrupole was used and data were acquired with a classical multiple-reaction monitoring (MRM) mode. Depending on the approach, the LOD values varied from 0.05 to 10 ng/mL. For the lowest concentrations, the proportion of molecules detected was systematically greater for the LR-MS approach, while those of HR-MSMS were better than those of HR-DIA. These differences in the LOD values were confirmed in a sample of 174 serums in which LR-MRM detected 89 compounds while HR-MSMS and HR-DIA detected 79 and 75 compounds, respectively. Nevertheless, for environmental and occupational purposes, HRMS approach could probably be efficient to detect most of pesticides and their metabolites in human serum and could be suitable for human biomonitoring studies or fundamental research exploring the impact of exposure to pesticides on human health.

Sanitary and Chemical Analysis of Drinking Water and Laboratory Control of the Content of Toxic Elements of Pesticides and Mycotoxins in Food Products

Relevance of the study: nutrition is the most important factor in maintaining health, normal growth and development of children and adolescents, preventing a number of diseases, maintaining high performance of the adult population, maintaining active longevity. Drinking water and food are necessary for the existence of humans and all life on Earth. Issues related to increasing responsibility for the effectiveness and objectivity of quality control of drinking water and food products are relevant in guaranteeing their safety for the health of consumers. Objectives of the study: to study the quality of drinking water and the efficiency of the water supply system in Osh in the period from 2020 to 2023; analysis of compliance of drinking water quality with sanitary and chemical standards; development of recommendations for improving the quality of water and the water supply system in Osh. Determination of toxic elements, pesticides and mycotoxins in food products, determination of physicochemical indicators and toxic elements in drinking water, pesticides and mycotoxins in food products was carried out in accordance with regulatory documents of GOST and the maximum permissible concentration. The test results showed the normal and permissible levels of pH, total iron, fluorides, hardness, dry residue, ammonia, nitrates, etc. in water, and the content of aflatoxin B1, the mass concentration of cadmium and lead, hexachlorane, dichlorodiphenyltrichloroethane in food products. For a more in-depth analysis, it is recommended to use additional data on climatic conditions, geological features of the region, as well as the demographic situation in Osh.

Determination of Residual Pesticides in Selected Grains, Fruits and Vegetables Commercially Sold in Eke Awka Market, Awka, Anambra State, Nigeria

Six samples from cucumber (Cucumis sativus), apple (Malus domestica), cabbage (Brassica oleracea), Tiger nuts (Cyperus esculentus), Beans (Phaseolus vulgaris), Green peas (Pisum sativum) were purchased from Eke Awka market, Awka in Anambra state, and were evaluated for their residual pesticides. Estimation of Pesticides residues were carried out using American Public Health Association Method. The result of the pesticide residues analysis showed that all the samples contain pesticide residues but the most prevalent one was Isopropylamine. The pesticide residues in beans have highest concentration of Isopropylamine (0.094 0.001%), followed by cucumber (0.058 0.01%) and then apple (0.040 0.001%) while the least was cabbage (0.023 0.001%). Among all samples studied, beans have the highest level of pesticide residues (0.245 mg/kg) followed by Apple (0.206 mg/kg) and cucumber (0.178 mg/kg) and least was cabbage (0.121mg/kg). Among all the pesticides studied, lindane was above maximum residue limit (0.01 mg/kg) in apple and tiger nut (0.048 0.001%) and 0.043 0.001%) respectively Conclusion: Pesticide residues in most of the samples analyzed were above limits which portends danger. There is urgent need to for action by policy makers and farmers respectively. Keywords: Pesticide residue, Grains, Fruits, Vegetables

A Robust Method for Simultaneous Determination and Risk Assessment of Multiresidual Pesticides in Fishery Products.

In this study, we developed and validated a multiresidue analytical method for the simultaneous detection of 24 pesticides in fishery products. Using the EN15662 extraction method and C18 as the adsorbent for purification, the validation results complied with Codex guidelines, achieving recovery rates between 70% and 120% and relative standard deviation values (%RSD) within 20%, indicating excellent performance. The limit of detection ranged from 0.25 to 0.8 ng/kg, and the limit of quantification was between 3 and 10 ng/g, providing sufficient sensitivity to comply with future regulatory standards. The calibration curves for all 24 pesticides exhibited great linearity (R2 > 0.98), also satisfying the Codex requirements. The matrix effect was less than 30% for some pesticides-within ±20%-indicating minimal interference from impurities. An analysis of 300 fishery samples from nine regions across South Korea detected lufenuron at 10 ng/g in eels; however, the risk assessment was below 0.19%, posing no significant hazard to public health. This newly developed analytical method proved effective for the multi-analysis of pesticide residues in fishery products, offering rapid and reliable monitoring of the import and export safety of fishery products.

Eco-friendly chitosan microspheres as a novel one-step sorbent for the rapid purification and determination of pesticides and veterinary drug multi-residues in aquatic products with HPLC-MS/MS

A modified QuEChERS method was developed to determine multi-class pesticide and veterinary residues in aquatic products. Chitosan microspheres were conveniently synthesized and utilized as the cleanup adsorbent in the QuEChERS procedure, showcasing rapid filtration one-step pretreatment ability for the determination of drug multi-residues in aquatic products. Compared to conventional synthetic sorbents, chitosan microspheres not only have good purification performance, but also have renewable and degradable properties. This novel sorbent worked well in the simultaneous determination of 95 pesticides and veterinary drug residues in aquatic products after being combined with an improved one-step vortex oscillating cleanup method. We achieved recoveries ranging from 64.0% to 115.9% for target drugs in shrimp and fish matrix. The limits of detection and quantification were 0.5–1.0 and 1.0–2.0 μg kg−1, respectively. Notably, hydrocortisone was detected with considerable frequency and concentration in the tested samples, underscoring the necessity for stringent monitoring of this compound in aquatic products.

Simultaneous electrochemical determination of carbendazim and thiabendazole pesticides based on UiO-66(Zr)-NH-OC-MWCNT 3D coated glassy carbon electrode

Simultaneous electrochemical determination of carbendazim and thiabendazole pesticides based on UiO-66(Zr)-NH-OC-MWCNT 3D coated glassy carbon electrode

Multiclass and multi-residue determination of pesticides and antibiotics in sediment from an aquacultural environment based on modified dispersive solid-phase extraction.

A quick, easy, cheap, effective, rugged, and safe method was developed for the multi-residue analysis of pesticides and antibiotics in aquaculture sediment using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The developed method is based on ultrasonic extraction with acetonitrile and phosphate buffer, salting with sodium chloride, and cleaning with dispersive solid-phase extraction adsorbent using primary secondary amine, C18, and graphitized carbon black, followed by HPLC-MS/MS detection. We optimized different extraction methods and the ratio of the cleanup adsorbents to achieve good recoveries at three spiking levels that ranged from 60.4% to 114% with a relative standard deviation below 15% (n=6). For all analytes, except for flufenoxuron, the limits of quantification were between 1 and 5µg/kg (dry weight). The validated method was successfully applied to real samples collected from 20 aquacultural ponds, confirming the feasibility of the proposed method. The concentrations of the target analytes in the sediments (dry weight) were in the ranges of 2.2-35.0µg/kg for sulfonamides, 0-409.1µg/kg for quinolones, 0-6.56µg/kg for macrolides, and 0-4.9µg/kg for pesticides. Moreover, the co-occurrence of pesticides and antibiotics may potentially pose a high risk to sediment-dwelling organisms in nine out of the 20 investigated locations.

Determination of pesticide residues in five different corn-based products using a single and simple solid–liquid extraction without clean-up steps followed by comprehensive two-dimensional liquid chromatography coupled to tandem mass spectrometry

Pesticide residues in food products are a critical issue concerning food safety. Recent studies have increasingly focused on developing selective, rapid, innovative, and environmentally friendly analytical methods for detecting pesticides in foodstuffs. This study presents a novel analytical method utilizing comprehensive two-dimensional liquid chromatography-tandem mass spectrometry for the simultaneous determination of one hundred and thirteen multiclass pesticides in corn products. The method simplifies the process with a single-step solid–liquid extraction and benefits from two-dimensional separation to enhance resolution and minimize matrix effects. The methodology was validated according to European Commission DG-SANTE (SANTE/11312/2021) and European Committee for Standardization (EN 15662, 2018) guidelines, obtaining acceptable analytical parameters. Limits of detection ranged from 0.2 µg/L to 30.2 µg/L and limits of quantification from 0.3 to 91.6 μg/L, all bellow regulatory limits. Accuracy, ranged from 60 to 120 % and precision, estimated by relative standard deviation, was consistently below 15.1 % in all cases. The applicability of the method was demonstrated by analyzing pesticides in five representative corn products (tortilla, corn flakes, corn cake, starch, and polenta). Sixteen pesticides were detected, all within the regulatory residue limits. Three metric tools were applied to assess the analytical process. Environmental sustainability was evaluated using the AGREE metric, while analytical performance and method applicability were assessed with the Red-Green-Blue and Blue Applicability Grade Index models, respectively, yielding promising scores (0.5, ≥ 0.55, and 0.65). These findings and the comparison to previous methods indicated that this approach represents a promising, alternative and user-friendly strategy for pesticide determination, offering effective productivity and reliable analytical performance.

Dispersive micro Solid-Phase extraction with Bimetallic Ni, Zn-MOF sorbent and gas chromatography method for Organophosphorus pesticide determination in environmental water samples

A dispersive micro solid-phase extraction coupled with the GC-FID method was developed to determine three Organophosphorus pesticides: Fenitrothion, Chlorpyrifos, and Diazinon. Various sorbents, including Fe3O4 NPs, Zn-MOF, Ni-MOF, Bimetallic Ni, Zn-MOF, and Fe3O4 NPs@SiO2@ Bimetallic Ni, Zn-MOF, were synthesized and evaluated for their extraction efficiency of OPPs. Fe3O4 NPs@SiO2@ Bimetallic Ni, Zn-MOF was identified as the optimal sorbent based on its performance. The affective factors in the procedure were optimized using one factor of the time and experimental design methods. The significant factors in this method included sorbent amount, extraction time, and desorption solvent volume with an optimum value of 37 mg, 8.3 min, and 231 µL, respectively. Under optimized conditions, the method exhibited distinct linear ranges for Fenitrothion, Chlorpyrifos, and Diazinon, ranging from 0.24 to 259, 0.17–234, and 0.25–247 ng mL−1, respectively, with high corresponding R2 values (0.9947, 0.9929, and 0.9943). The limits of detection (LOD) were determined based on three times the standard deviation of the blank sample divided by the slope of the calibration curve for each OPP to be 0.07, 0.05, and 0.07 ng mL−1 for Fenitrothion, Chlorpyrifos, and Diazinon, respectively, while the limits of quantification (LOQ) were 0.24, 0.17, and 0.25 ng mL−1. Precision was assessed by calculating intra-day and inter-day relative standard deviation (RSD%) values in one day and three consecutive days with three replicates of each analysis for three concentrations of 10, 25, and 50 ng mL−1, which were found to be below 4.27 %, 4.35 %, and 4.32 % for Fenitrothion, Chlorpyrifos, and Diazinon, respectively, for intra-day analysis, and below 5.43 %, 5.11 %, and 5.29 % for inter-day analysis, respectively. Additionally, the enrichment factor (EF) values for Fenitrothion, Chlorpyrifos, and Diazinon with a concentration of 20 ng mL−1 were determined to be 78.6, 82.4, and 75.7, respectively. Analysis of spiked real samples in two concentrations of 5.0 or 25.0 ng mL−1, such as tap water, river water, dam water, and well water, revealed recovery percentages in the range of 91.2 % to 97.7 %, with relative standard deviations ranging from 3.79 % to 4.98 %, further validating the method’s reliability for practical applications. Overall, the method provides wide linearity, low LODs and LOQs, responsible RSDs, high EFs, and proper recovery percentages for determining OPPs.

Electro-generating Cu2+ ions based on electrochemically modified CPE for the determination of malathion pesticide using valid SW-ASV method

This work investigates the validation of the SW-ASV method for the determination of malathion organophosphorus pesticide based on an electrochemically modified (CPE) carbon paste electrode with copper metal. The surface of the modified CPE was constructed by electrodepositing the copper layer at the accumulation step in 1-mM CuSO4.5H2O, PBS at pH 6.6, E accumulation: − 0.8 V, and Taccumulation 240 s. The determining step was performed by adding different concentrations of malathion pesticide and applying the potential toward more positive potential at (− 0.8–+ 1.4 V) to enhance the oxidation of Cu0 metal. It was noticed that the malathion concentration gradient enhances the oxidation peak current of copper at + 0.03 V gradually. SW-ASV method validation was performed at a linearity range confined in (1–10 µM). An analytical curve was constructed and R2 was equal to 0.99995 with good fitted linear relationship. LOD and LOQ were calculated to be 0.0247 and 0.08236 µM, respectively. ANOVA for two sets of measurements using the standard gas chromatographic method and the suggested SW-ASV method was demonstrated via the calculations of F-value and t-value. F and t-values were calculated to be 1.698 and 0.289, respectively, which did not exceed the tabulated F and t-values resulting in the great similarity of results and ensuring the reliability of the suggested test method. This valid SW-ASV method was used to perform the routine analysis of the 95% technical grade and the pesticide formulation 57% emulsion concentrate of the malathion. Valid results were achieved with satisfactory limits of accuracy and precision.Graphical abstract

Optimization and Validation of Analytical Methodology for Determination of Pesticides in Grape, Must and Wine Samples with QuEChERS Extraction and Gas Chromatography–Mass Spectrometry

This study is focused on the optimization and application of an analytical methodology for the determination of 15 selected pesticides in three substrates during the vinification process. QuEChERS extraction was used followed by GC-MS to develop a simple and rapid method for the determination of these compounds. The optimized methodology was validated, providing for all selected pesticides excellent linearity, recoveries ranging between 60.9% and 95.0% and LOQs lower than 50 ng g−1 f for all substrates. The developed methodology was tested on real samples of grapes, must and wine obtained from a winery in the Epirus region. The results indicated the existence of some of the selected pesticides at comparatively low levels in contrast to the valid MRLs.

Determination of multi-residue pesticides in dairy products using single-step emulsification/demulsification clean-up strategy combined with low-pressure gas chromatography-tandem mass spectrometry

In this study, a simple, sensitive, and rapid method was developed for the simultaneous determination of 99 kinds of pesticides in fatty milk samples. This novel emulsification-demulsification clean-up approach, coupled with an automatic demulsification-dehydration cartridge, allowed rapid single-step clean-up operation and high throughput. It also achieved effective and selective removal of lipids. The analysis was performed using low-pressure gas chromatography-tandem mass spectrometry (LPGC–MS/MS). Based on the optimal conditions, the targeted pesticides showed good linearity in the range of 5–250 μg/kg, with recoveries of 70–120% at spiking levels of 5, 10, and 20 μg/kg in cow milk, goat milk, and almond milk, respectively. The limit of quantification for most pesticides was 5 μg/kg, and the RSDs were lower than 20%. Analysis of real dairy products obtained from local markets revealed a potential risk in plant-derived almond milk, but no significant risks were found for cow and goat milk.

A Recyclable Luminescent MOF Sensor for On-Site Detection of Insecticide Dinotefuran and Anti-Parkinson's Drug Entacapone in Various Environmental and Biological Specimens.

The monitoring and precise determination of pesticides and pharmaceutical drugs and their residues have become increasingly important in the field of food safety and water contamination issues. Herein, a fluorescent aluminium MOF-based sensor (1) was developed for the selective recognition of neonicotinoid insecticide dinotefuran and anti-Parkinson's drug entacapone. Guest-free MOF 1' exhibited ultra-fast response (<5 s) and ultra-low detection limits of 2.3 and 7.6 nM for dinotefuran and entacapone, which are lower than the previously reported MOF-based sensors. In the presence of other competitive analytes, great selectivity was achieved towards both analytes. The probe was recyclable up to five cycles. The sensing ability was explored towards entacapone in human serum, urine and dinotefuran in real soil, rice, honey samples, different fruits, vegetables, real water specimens and a wide range of pH media. A low-cost, handy MOF-based polymer thin-film composite (1'@PVDF-PVP) was developed for the on-site detection of dinotefuran and entacapone. Mechanistic studies involving analytical techniques and theoretical calculations suggested that FRET and PET are the probable reasons for entacapone sensing whereas IFE is responsible for dinotefuran detection. The entire work presents a low cost, multi-use photoluminescent sensor of entacapone and dinotefuran to address the environmental pollution.

A novel halloysite nanotubes-based hybrid monolith for in-tube solid-phase microextraction of polar cationic pesticides

The accurate determination of polar cationic pesticides in food poses a challenge due to their high polarity and trace levels in complex matrices. This study hypothesized that the use of halloysite nanotubes (HNTs) can significantly enhance the extraction efficiency and sensitivity of these analytes because of their rich hydroxyl groups and cation exchange sites. Therefore, we chemically incorporated HNTs with organic polymer monoliths for in-tube solid-phase microextraction (SPME). This novel hybrid monolith extended service life, improved adsorption capacity, and exhibited excellent extraction performance for polar cationic pesticides. Based on these advancements, a robust and sensitive in-tube SPME-HILIC-MS/MS method was constructed to determine trace levels of polar cationic pesticides in complex food matrices. The method achieved limits of detection of 1.9, 2.1, and 0.1 μg/kg for maleic hydrazide, amitrole, and cyromazine, respectively. The spiked recoveries in five food samples ranged from 80.2 to 100.8%, with relative standard deviations below 10.7%.

Method optimization for a simultaneous determination of neonicotinoid, carbamate/thiocarbamate, triazole, organophosphate and pyrethroid pesticides and their metabolites in urine using UPLC-MS/MS

An accurate and sensitive method for the determination of a total of 23 pesticides and their metabolites in human urine has been optimised. The methodology is based on a previously published method based on solid-phase extraction with methanol and acetone followed by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) in the selected reaction mode (SRM) with both positive and negative electrospray ionization (ESI+/-). The detection settings of the previous method, which allowed to determine the metabolites from 6 organophosphate and 2 pyrethroid pesticides, were optimised in order to include further pesticide groups, such as 11 neonicotinoids, 3 carbamates/thiocarbamates and 2 triazoles. The 5-windows method enduring 22 min was optimized with acceptable results in relation to accuracy (recoveries >75 %), precision (coefficients of variation <26 %) and linearity (R2> 0.9915). The limits of detection ranged between 0.012 ng/mL and 0.058 ng/mL. Samples from the German External Quality Assessment Scheme (G-EQUAS) encompassing 2 pyrethroids, 2 organophosphate and one neonicotinoid (6-chloronicotinic acid, a common metabolite of imidacloprid and acetamiprid) were analysed, and the latter, included in this newest optimization, provided good reference results. The method is optimal as a human biomonitoring tool for health risk assessment in large population surveys.

Effective extraction of pyrethroid pesticides from cabbages using Fe3O4@NU-1000 and adsorption mechanism: An experimental and theoretical study

In this paper, a magnetic zirconium-based MOFs (Fe3O4@NU-1000) with good water stability was prepared for effective extraction of pyrethroid pesticides from vegetables. Characterization results showed Fe3O4@NU-1000 has a high specific surface area (435.34 m2·g−1) and a large pore size (4.88 nm), which provides abundant adsorption sites for pesticides molecules. Fe3O4@NU-1000 can achieve rapid magnetic separation from solution within 1 min, greatly reducing the extraction time of pyrethroid pesticides. The results of adsorption kinetics and isotherms showed that the adsorption process of pyrethroid pesticides on Fe3O4@NU-1000 was monolayer adsorption and physisorption. The maximum adsorption capacities of Fe3O4@NU-1000 for beta-cyfluthrin, lambda-cyhalothrin, permethrin, and bifenthrin were up to 1159.11, 1194.16, 1151.48, and 1181.74 mg·g−1, respectively. Molecular dynamics simulations showed that adsorption is driven by hydrophobic interaction. Van der Waals forces and hydrogen bonding accelerate pesticide molecules to approach the surface, and π–π interactions enable stable adsorption of pesticide molecules within the triangular and hexagonal micropores of NU-1000. DFT calculations confirmed that pesticide molecules predominantly adsorb stably within the pores of Fe3O4@NU-1000 through π–π interactions, with additional contributions from CH3–π and Cl–π interactions. Finally, a simple and sensitive method was established for the determination of pyrethroid pesticides in cabbage samples using Fe3O4@NU-1000 based magnetic solid-phase extraction and high-performance liquid chromatography. It provided low limit of detection (0.0011–0.0058 μg·mL−1), a wide linear range (1–25 μg·mL−1), and satisfactory recoveries (81.35–98.64 %), which can achieve effective extraction and trace detection. This study provides a magnetic MOFs material for extraction of pesticides and reveals its adsorptive mechanism at molecular level, which is helpful for rational design of more pretreatment materials for pesticides detection in complex food matrices.

Simple and Fast Determination of Carbaryl Pesticide in Commercial Topical Formulations by Capillary Electrophoresis

A novel analytical method using capillary zone electrophoresis (CZE) for simple and fast determination of the pesticide carbaryl in commercial topical formulations was developed and validated. The carbaryl was previously hydrolyzed quantitatively under an alkaline medium (NaOH solution) to form 1-naphthol, which was separated and quantified by CZE with spectrophotometric detection at 214 nm. Optimization of the hydrolysis reaction regarding time and NaOH concentration was conducted. The CZE separation was achieved in less than 3 min using a bare silica capillary (60 cm total length) and a 10 mmol L-1 sodium borate buffer (pH 9.3) as background electrolyte. The proposed CZE method was linear in the 0.25 to 70 mg L-1 concentration range, as attested by a coefficient of determination (R2) higher than 0.999 and confirmed by the lack of fit test. Recovery tests at three concentration levels provided recovery percentages ranging from 80 to 115%, indicating acceptable accuracy. The limits of detection (LOD) and quantification (LOQ) were 0.08 and 0.25 mg L-1, respectively. The proposed CZE method was successfully applied for carbaryl determination in commercial samples of topical formulations such as powders and dry bath gel.