Determination Of Pesticides Research Articles

Dispersive liquid-liquid microextraction coupled with microfluidic paper-based analytical device for the determination of organophosphate and carbamate pesticides in the water sample.

A microfluidic paper-based analytical device (µ-PAD) is a promising new technology platform for the development of extremely low-cost sensing devices. However, it has low sensitivity that might not enable to measure maximum allowable concentration of various pollutants in the environment. In this study, a dispersive liquid-liquid microextraction (DLLME) was developed as a preconcentration method to enhance the sensitivity of the µ-PAD for trace analysis of selected pesticides. Four critical parameters (volume of n-hexane and acetone, extraction time, NaCl amount) that affect the efficiency of DLLME have been optimized using response surface methodology. An acceptable mean recovery of 79-97% and 83-93% was observed at 1µgL-1 and 5µgL-1 fortification level, respectively, with very good repeatability (2.2-6.01% RSD) and reproducibility (5.60-10.41% RSD). Very high enrichment factors ranging from 317 to 1471 were obtained. The limits of detection for the studied analytes were in the range of 0.18-0.41µgL-1 which is much lower than the WHO limits of 5-50µgL-1 for similar category of analytes. Therefore, by coupling DLLME with µ-PAD, a sensitivity that allows to detect environmental threat and also that surpassed most of the previous reports have been achieved in this study. This implies that the preconcentration step has a paramount contribution to address the sensitivity problem associated with µ-PAD.

Determination of pesticides and their degradation products in sediment samples by accelerated solvent extraction and solid-phase extraction with high-performance liquid chromatography-high-resolution mass spectrometry.

A new sensitive and selective methods was developed to quantify different types of pesticides and their degradation products in sediment. The method developed was optimized and modified based on the accelerated solvent extraction, followed by the solid-phase extraction clean-up technique. High-performance liquid chromatography coupled with mass spectrometry was used for analysis. The influence of various parameters on the extraction process was investigated, including the extraction temperature, extraction solvent, purification column and purification solvent, etc. Under the optimal conditions, the relative recoveries of the pesticides and their degradation products ranged from 80 to 106% for spiked blank sediment and environmental sediment samples with relative standard deviations of 1-9%. The method displayed low method detection limits for both sediment matrices and achieved good linearity over the tested range of concentrations. The physical and chemical properties of sediment showed that high content of sediment water content and humic acid would affect the extraction efficiency of sample pretreatment. The method was applied to environmental sediment to quantify pesticide residues in the samples. Based on the instrument and method performance validation results, the developed methods can be applied in environmental pesticide residue analysis, thus providing a scientific method for the detection of sediment samples.

A simple approach for pesticide residues determination in green vegetables based on QuEChERS and gas chromatography tandem mass spectrometry

Preparing matrix-matched calibration curves for each matrix type makes multiresidue methods for pesticides determination in foods a labor-intensive endeavor. Herein, a highly efficient method for the purification of plant extracts (6 mL) based on QuEChERS, with 900 mg anhydrous MgSO4, 300 mg C18, 300 mg ChloroFiltr at d-SPE stage, combined with gas chromatography with tandem mass spectrometry for the determination of 164 pesticides in vegetables of varying chlorophyll content was developed. This method enables the application of a matrix-matched curve prepared in one type of matrix for the determination of pesticides in food samples with different chlorophyll contents. Method validation adhered to the requirements of SANTE/12682/2019 document (recoveries: 70–120%, RSD<20%, LOQ: 0.005 mg/kg, matrix effect: ± 20%, uncertainty<50%).The method was employed for pesticides determination in vegetables purchased from local markets. In 27 samples, pendimethalin was the most abundant compound determined (9 samples) in the concentration range of 0.007–0.065 mg/kg, followed by difenoconazole (5 samples) in the concentration range of 0.013–0.025 mg/kg. The highest concentration exceeding the maxium residual level was found for chlorpyrifos (0.110 mg/kg in dill) and for tebuconazole (0.009 mg/kg in Chinese cabbage). None of the samples examined revealed the simultaneous occurrence of more than three pesticides.

Assessment of the safety of the use of plant protection products - derivatives of aromatic amines based on micellar catalytic reactions

The features of the interaction of aromatic aldehydes (by the example of p- dimethylaminocinnamaldehyde) with pesticides, derivatives of aromatic amines and ureas were studied; the optimal conditions for the reaction were determined; the influence of various types of surface-active substances on the state of the reaction products was studied; the choice of the type of anionic surfactant to improve the analytical characteristics of the reaction products was justified. They are developed highly efficient methods for the photometric and test determination of individual pesticides, derivatives of aromatic amines and ureas, at the level of MAC fractions in micellar surfactant solutions.

Bursting bubble flow microextraction combined with gas chromatography for determination of organochlorine pesticides in aqueous samples

Bubble-bursting flow microextraction (BBFME) is a simple and powerful microextraction method that conforms to the principles of green analytical chemistry (GAC). This method, combined with GC, is used for extraction, pre-concentration, and determination of some organochlorine pesticides (OCPs) in aqueous samples. In this method, the target analytes are transferred to the surface of the sample solution by the flow of gas bubbles. After the bubbles burst, the analytes disperse into the upper space and are finally collected and extracted. One of the unique properties of gas bubbles is the creation of a two-phase liquid–gas system, whereby the extraction process occurs at the liquid–gas interface where analytes interact with gas molecules in the bubble. In this study, a new method based on the availability of gas bubbles was proposed and investigated. The conditions affecting BBFME performance, including extraction time, the effect of ionic strength, and sample pH were investigated. Under optimal conditions, the dynamic linear range was 0.74–100.0 μg L-1, and the limit of detection and limit of quantification were 0.24–0.33 and 0.74–0.98 μg L-1, respectively. The range of enrichment factor and recovery under optimal conditions was between 228 and 273 and between 82.1 % and 98.2 %, respectively. Finally, using the BBFME method, the toxins simazine, γ-BHC, alachlor, aldrin and dieldrin were successfully extracted from various aqueous samples with satisfactory relative recoveries ranging from 95.3 to 105.1 %.

Magnetic silicon carbide nanocomposite as a sorbent in magnetic dispersive solid phase extraction followed by dispersive liquid–liquid microextraction in the gas chromatographic determination of pesticides

A magnetic silicon carbide nanocomposite based-magnetic dispersive solid phase extraction approach using aspiration/dispersion cycles was proposed. Several pesticides including diazinon, ametryn, chlorpyrifos, hexaconazole, diniconazole, tebuconazole, and triticonazole were extracted by this method from different samples. The analytes were extracted by a few mg of the prepared nanocomposite from the sample solution. The sample solution and adsorbent contact area was increased by performing aspiration/dispersion cycles. The nanocomposite particles were separated from sample solution using a neodymium magnet. Then an appropriate volume of an organic solvent was added onto the nanocomposite particles to desorb the analytes. Then, the obtained eluate was utilized in the next microextraction method to achieve high sensitivity and enrichment factor. Gas chromatography equipped with mass spectrometry was used for determination of the extracted analytes. Validation values considering ICH protocol illustrated that limits of detection and quantification were within the ranges of 0.06–0.33 and 0.19–1.0 ng mL−1. Good precision (relative standard deviations ≤ 7.0 %), acceptable linearity (r2 ≥ 0.992), high enrichment factors (600–850), extensive linear ranges, and acceptable extraction recoveries (60–85 %) were obtained. This approach was done on different real samples and chlorpyrifos and diazinon were determined in some of them.

Application of Fe3O4@CNFs combined with deep eutectic solvent-based dual microextraction: a novel and green strategy for rapid determination of pesticides in edible oil samples.

A novel, green, and effective strategy employing Fe3O4-modified carbon nanofibers (CNFs) combined with deep eutectic solvent (DES) is proposedas an extraction agent to extract five pesticides in edible oil samples via dual microextraction modes, followed by high-performance liquid chromatography for determination. The Fe3O4@CNFs nanomaterial and a sequence of hydrophilic DES were prepared at first and then characterized by multiple techniques. Subsequently, the extraction performance of DES and Fe3O4@CNFs-DES was compared and Fe3O4@CNFs-DES exhibited better extraction ability. After that, several influencing parameters such as the composition of DES, the amount of Fe3O4@CNFs-DES, the dispersion methods, and the extraction time were investigated and optimized. Eventually, Fe3O4@CNFs as the solid adsorbent combined with tetrabutylammonium chloride-lactic acid-based DES as the extraction solvent were selected to extract target pesticides from oil samples. The established method received good linearity in the range 25-1000ng·g-1. The limits of detection for all analytes were in the range 2.25-7.50ng·mL-1. Satisfactory recoveries of target pesticides were obtained (ranging from 82 to 117%) with a relative standard deviation of 0.26-9.46%. The proposed method has been successfully applied to the rapid detection of target pesticides in oil samples, demonstrating its great potential for quick screening and analysis.

General Method for Pesticide Recognition Using Albumin-Based Host-Guest Ensembles.

The massive use of pesticides nowadays has led to serious consequences for the environment and public health. Fluorescence analytical methods for pesticides are particularly advantageous with respect to simplicity and portability; however, currently available fluorescence methods (enzyme-based assays and indicator displacement assays) with poor universality are only able to detect few specific pesticides (e.g., organophosphorus). Making use of the multiple flexible and asymmetrical binding sites in albumin, we herein report a set of multicolor albumin-based host-guest ensembles. These ensembles exhibit a universal but distinctive fluorescent response to most of the common pesticides and allow array-based identification of pesticides with high accuracy. Furthermore, the simplicity, portability, and visualization of this method enable on-site determination of pesticides in a practical setting. This albumin host strategy largely expands the toolbox of traditional indicator displacement assays (synthetic macrocycles as hosts), and we expect it to inspire a series of sensor designs for pesticide detection.

Nanofibrous Online Solid-Phase Extraction Coupled with Liquid Chromatography for the Determination of Neonicotinoid Pesticides in River Waters.

Polymeric nano- and microfibers were tested as potential sorbents for the extraction of five neonicotinoids from natural waters. Nanofibrous mats were prepared from polycaprolactone, polyvinylidene fluoride, polystyrene, polyamide 6, polyacrylonitrile, and polyimide, as well as microfibers of polyethylene, a polycaprolactone nano- and microfiber conjugate, and polycaprolactone microfibers combined with polyvinylidene fluoride nanofibers. Polyimide nanofibers were selected as the most suitable sorbent for these analytes and the matrix. A Lab-In-Syringe system enabled automated preconcentration via online SPE of large sample volumes at low pressure with analyte separation by HPLC. Several mat layers were housed in a solvent filter holder integrated into the injection loop of an HPLC system. After loading 2 mL sample on the sorbent, the mobile phase eluted the retained analytes onto the chromatographic column. Extraction efficiencies of 68.8–83.4% were achieved. Large preconcentration factors ranging from 70 to 82 allowed reaching LOD and LOQ values of 0.4 to 1.7 and 1.2 to 5.5 µg·L−1, respectively. Analyte recoveries from spiked river waters ranged from 53.8% to 113.3% at the 5 µg·L−1 level and from 62.8% to 119.8% at the 20 µg·L−1 level. The developed methodology proved suitable for the determination of thiamethoxam, clothianidin, imidacloprid, and thiacloprid, whereas matrix peak overlapping inhibited quantification of acetamiprid.

Application of ecofriendly magnetic nanocomposite synthesized from natural materials for separation and determination of diazinon pesticide in real water samples

ABSTRACT In this study, a cheap, novel, ecofriendly and effective nanosorbent was synthesised with natural materials such as sand beach and eggshell for diazinon determination in natural water. The synthesised nanosorbent was successfully characterised using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning- electron microscopy (SEM), vibrating sample magnetometer (VSM) and Brunauer–Emmett–Teller (BET) methods. Effective parameters were optimised for the extraction of diazinon and determination was done by UV-Vis spectroscopy at 248 nm. The method was linear in the range of 50–400 µg L−1 and the limit of detection was 6.9 µg L−1. Adsorption kinetic and isotherm studies were performed. Also, for measurement of diazinon in water samples of Gilan province, sampling was performed from important points such as river water, Anzali lagoon, well water, agricultural streams, and tap water. The results shows good spiked recovery (97.6–103.4%) in all samples. The accuracy of the method was also confirmed by the student’s t -test with HPLC analysis of real samples.

Evaluation of green silicone surfactant-based vortex assisted dispersive liquid-liquid microextraction for sample preparation of organophosphorus pesticide residues in honey and fruit sample.

A vortex-assisted surfactant enhanced emulsification liquid-liquid microextraction based on non-ionic silicone surfactant was successfully developed for the determination of organophosphorus pesticides in food samples coupled to gas chromatography-mass spectrometry. A new type of non-ionic silicone surfactant composed of polysiloxane chains was employed as a green emulsifier to facilitate the emulsification of extraction solvent into the sample matrix, thereby intensifying the mass transfer of target analytes into the organic phase. The variables that affect the extraction were systematically optimized: 80 μl of hexane and 0.5% (v/v) of silicone surfactant were used as extraction solvent and surfactant respectively, the solution was mixed well under vortex agitation for 1 min with the addition of 4% (w/v) sodium sulfate. Under optimum conditions, the linearity of the method was obtained in the range of 0.1-200 μg/kg with a good coefficient of determination varying from 0.9986 to 0.9996. The limit of detection and the limit of quantitation were between 0.008-0.1 and 0.02-0.3 μg/kg, respectively. Application of the proposed method to real samples gave satisfactory recovery values (80%-118%) for the target analytes. The suggested approach has also proven to be convenient, expeditious, and environmentally benign.

Determination of pesticides in hydroponic water for environmental phytoremediation

This study validated a simple, and fast method by High Performance Liquid Chromatography with Diode Array Detector (HPLC -DAD) for pesticide phytoremediation analysis. The method was developed in water and in a hydroponic medium. Sample extraction and concentration were performed by Solid Phase Extraction (SPE) with Strata C18-E type cartridges. The SPE-HPLC-DAD method was successfully applied in the detection and quantification of quinclorac, 2,4-D, propanil, bentazon, clomazone and tebuconazole in water and hydroponic medium for 14 days. The method presented excellent results with the linearity of 0.9969 - 0.9994 and the lowest limit of detection (LOD) and quantification (LOQ) of pesticides was 1.7 μg/L and 5.0 μg/L, respectively with RSD &lt;11.92%. The average recovery obtained ranged from 77.62% to 109.73% and RSD &lt;12.70%. A Lactuca sativa species promoted phytoremediation on the 7th day for 2,4-D and tebuconazole and on the 14th day for clomazone.

Development of a nanocopper-decorated laser-scribed sensor for organophosphorus pesticide monitoring in aqueous samples

Organophosphorus pesticides are widely used in industrial agriculture and have been associated with water pollution and negative impacts on local ecosystems and communities. There is a need for testing technologies to detect the presence of pesticide residues in water sources, especially in developing countries where access to standard laboratory methods is cost prohibitive. Herein, we outline the development of a facile electrochemical sensor for amperometric determination of organophosphorus pesticides in environmental water samples. A three-electrode system was fabricated via UV laser-inscribing on a polyimide film. The working electrode was functionalized with copper nanoparticles with affinity toward organophosphate compounds. The sensor showed a limit of detection (LOD) of 3.42 ± 1.69 µM for glyphosate, 7.28 ± 1.20 µM for glufosinate, and 17.78 ± 7.68 µM for aminomethylphosphonic acid (AMPA). Sensitivity was highest for glyphosate (145.52 ± 36.73 nA⋅µM−1⋅cm−2) followed by glufosinate (56.98 ± 10.87 nA⋅µM−1⋅cm−2), and AMPA (30.92 ± 8.51 nA⋅µM−1⋅cm−2). The response of the sensor is not significantly affected by the presence of several ions and organic molecules commonly present in natural water samples. The developed sensor shows promising potential for facilitating environmental monitoring of organophosphorus pesticide residues, which is a current need in several parts of the world.Graphical

Microfluidic Paper Based Analytical Devices for the Detection of Carbamate Pesticides.

Microfluidic paper-based analytical devices (μ-PADs) are a new technology platform for the development of extremely low-cost sensing applications. In this study, μ-PADs has been developed for quantitative determination of carbamate pesticides. Key experimental parameters including concentration and volume of acetylcholinesterase, acetylthiocholine iodide and 5,5'-dithiobis-(2-nitrobenzoicacid), incubation time and image capturing time were systematically optimized. Under optimal conditions, the method showed wide range of linearity (0.25-16mg/L), repeatability (4%-5% RSD) and intermediate precision (7%-10% RSD). Limit of detection was observed to be 0.4, 0.24 and 0.46mg/L for carbaryl, carbosulfan and furathiocarb, respectively. An acceptable mean recovery (87% to 94%) was observed for the three pesticides at 1mg/L fortification level. The results reveal that the developed method requires minimal reagents, simple and is easy to handle. It can be used for the quantification of carbamate pesticides in resource limited laboratories without the need for the conventional analytical instruments.

Current Role of Mass Spectrometry in the Determination of Pesticide Residues in Food

The extensive use of pesticides represents a risk to human health. Consequently, legal frameworks have been established to ensure food safety, including control programs for pesticide residues. In this context, the performance of analytical methods acquires special relevance. Such methods are expected to be able to determine the largest number of compounds at trace concentration levels in complex food matrices, which represents a great analytical challenge. Technical advances in mass spectrometry (MS) have led to the development of more efficient analytical methods for the determination of pesticides. This review provides an overview of current analytical strategies applied in pesticide analysis, with a special focus on MS methods. Current targeted MS methods allow the simultaneous determination of hundreds of pesticides, whereas non-targeted MS methods are now applicable to the identification of pesticide metabolites and transformation products. New trends in pesticide analysis are also presented, including approaches for the simultaneous determination of pesticide residues and other food contaminants (i.e., mega-methods), or the recent application of techniques such as ion mobility–mass spectrometry (IM–MS) for this purpose.

An integrative review on the analysis of pesticide multiresidues in sweet pepper samples using the QuEChERS method and chromatographic techniques

Since foods are complex matrices that contain pesticides of different classes, multiresidue sample preparation methods such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) are used and modified to obtain more accurate and sensitive results. This work was developed through an integrative review in the journal databases Capes, Science Direct, Scielo, and Scientia Chromatographic, from 2011 to 2021, to answer the following question: “What is the most efficient and advantageous sample preparation method for the determination of multiresidue pesticides of interest in sweet pepper samples, when chromatographic techniques are used for detection?” The sweet pepper was chosen because the Pesticide Residue Analysis in Food Program (PARA) suggests that it is the sample with the highest percentage of irregularities related to active ingredients not allowed or above the Maximum Residue Limit (MRL). A total of 391 articles were found, 11 of which met the inclusion criteria established. Several analyses were studied. The organophosphates were the most studied class of pesticide, with seven articles. In addition, there was a predominance of nonpolar analytes (log Kow &gt; 1). The use of different extracting solvents, such as methanol, acetonitrile, ethyl acetate, and acetone, was observed, with acetonitrile presenting the best analytical parameters in most cases. The use of different sorbents such as secondary and primary secondary amine (PSA), ocatadecyllane (C18), graphite carbon (GCB), and carbon black was noted, as well. The authors highlight the difficulties in the analysis when the matrix effect is significant (except for fensulfothion, tensulfothion, flonicamid, and its metabolite TFNA-AM) and the degradation of analytes through the analysis process (flonicamid, captan, folpet, thiophanate methyl and benomyl). Finally, the statistical test Analysis of Variance (ANOVA) was used to identify if there was a significant difference between the different methods used for the same analysis or when the same method used for the different analytes.

Organochlorine Pesticide Characterisation of Emede Wetland Isoko South Delta for Pen Aquaculture in Secondary Schools as an Emerging Trend in Vocational and Technical Education in the 21st Century Nigeria

This study is an ex-post facto research that investigated the organochlorine pesticides content of Emede wetland for its suitability for pen aquaculture in secondary school. The study answered 3 research questions and tested a hypothesis. To achieve this, the research area Emede wetland was mapped out into research cells. From each of the research cells, water samples were collected from 10 sampling spots, bulked and a composite drawn and fixed with HNO3 and stored in ice cooled boxes for laboratory analysis. The analytical standards adopted for the study were USEPA, APHA and ASTM and the analytical instrument deployed for determination of the organochlorine pesticides was EPA 8081 ECD. The mean results obtained are as follows: adrin 0.76±1.4µg/l, diedrin 1.26±0.30 µg/l, DDT 2.13±0.42 µg/l, endrin 0.62±0.55 µg/l and heptachlor 2.13±0.42 µg/l. The results obtained were subjected to test of significance with ANOVA at 0.05 level of significance deploying SPSS model 21. The p-value is 0.31 thus rejecting Ho. The study recommends that pen aquaculture should not be implemented in Emede wetland, the pollutions source should be identified and blocked and remediation should be carried out in the wetland to resuscitate the wetland to its hitherto healthy status.

Matrix‐induced sugaring‐out liquid‐liquid microextraction coupled with high‐performance liquid chromatography for the determination of organophosphorus pesticides in fruit jams

AbstractA rapid and easy analytical method for the determination of organophosphorus pesticides (fenitrothion, phosalone, profenofos, and chlorpyrifos) in fruit jams was developed using sugaring‐out liquid‐liquid microextraction followed by high‐performance liquid chromatography with ultraviolet detection. Acetonitrile was the only chemical used in the sample pretreatment step. The high sugar content of the sample matrix highly accelerated the extraction process as it simply triggered phase separation. The optimized sample treatment involved mixing 600 μl of ACN/water mixture (50/50%, v/v) with 1 g of jam sample, shaking for 0.5 min at 2500 rpm, and then centrifuging the sample for 5 min at 2500 × g. Under the optimal conditions, the extraction recoveries in the range of 81%–89% were achieved for the analytes. Good linearity in a range of 50–5000 μg/kg (r2 ≥ 0.9992) and limits of detection less than 25 μg/kg were obtained. Recovery assays for spiked commercial jams made from cherry, strawberry, blackberry, apricot, and blueberry provided recoveries from 89% to 107%.

Indirect chronovoltametric dosage of alkaline earth metals. The contribution of the chemist Ion Vatamanu to the development of electrochemical methods of analysis

The paper presents the results of a series of investigations on the indirect chronovoltametric dosing of alkaline earth metals, carried out in the Laboratory of the Analytical Chemistry at the Institute of Chemistry, currently called the Laboratory of Physicochemical Methods of Research and Analysis, conducted in 1971–1993 by the doctor of chemical sciences Ion Vatamanu. During the elaboration of the presented polarographic methods for determining the ions of alkaline-earth metals, a series of techniques were used to increase the sensitivity and selectivity of the determination. Based on two indirect polarographic methods for measuring alkaline earth metals, developed by Ion Vatamanu and coworkers and analyzed in this paper, two fundamental physicochemical principles were applied: (I) anion-induced adsorption of ligands adsorbed on the electrode surface and (II) thermodynamic determination of the optimal dosing conditions by calculating the conditional constants or the equilibrium chemical composition of complex reactant systems. The developed methods were used in the electrochemical analysis of standard alloy samples based on various metals, in the analysis of semiconductor systems, ferrous metals, nickel electrolytes, copper plating, cadmium plating, chromium plating, aluminum oxidation, wastewater analysis in galvanic baths, clays and limestones from Moldovan deposits, determination of pesticides, tanning extracts, dyes for the textile industry, etc.

Development of solid phase extraction with carbon nanoonion-polyaniline composite sorbent followed by microextraction method for the extraction of pesticides residues before gas chromatography

Organophosphate and triazole compounds are among the pesticides and fungicides that are classified as highly toxic materials because of their chronic and dangerous effects at low and moderate oral doses. Therefore, the measurement and extraction of small amounts of these compounds are of great importance for human and environmental health. In the present study, solid-phase extraction (SPE) was performed with carbon nano onion (CNO)-polyaniline (PANI) nanocomposite sorbent for the extraction of residual organic pesticides before gas chromatography (GC), so CNO was synthesized and covered with a layer of PANI for this purpose. The synthesized sorbent was analyzed and studied using different characterization methods. The prepared sorbent was used to extract pesticides from an aqueous medium. Then, for further preconcentration, the eluent of the SPE column was followed by a dispersive liquid-liquid microextraction (DLLME) method that had acceptable repeatability to the point that a wide linear range in 0.1–1000 μg l−1 (R2 > 0.99) was obtained for most analytes. Finally, pesticides determination in rainwater, apple juice, and cherry juice samples was conducted by the developed method.