Pesticides In Environmental Samples Research Articles

A state-of-the-art review of trends in molecularly imprinted polymers in the clean-up of pesticides in environmental samples

A state-of-the-art review of trends in molecularly imprinted polymers in the clean-up of pesticides in environmental samples

Synthesis of pyrochlore-type La2Sn2O7@GO for the in-situ profiling of organophosphate pesticides paraoxon ethyl in environmental samples

The detection and monitoring of organophosphate pesticides in environmental samples are of paramount importance due to their potentially harmful effects on human health and ecosystems. In this study, we present the detection of paraoxon ethyl (POE), a widely used organophosphate pesticide, utilizing an electrochemical method. We synthesized graphene oxide-incorporated pyrochlore-type lanthanum stannate (La2Sn2O7@GO) as a sensing material for enhanced detection sensitivity and selectivity. The electrochemical detection of POE was performed using a glassy carbon electrode modified with the synthesized nanocomposite. The modified electrode La2Sn2O7@GO/GCE exhibited a remarkable electrochemical response towards POE, showing a significant reduction potential and an increase in the peak current compared to the bare and other modified electrodes. The proposed electrochemical method showed excellent detection sensitivity and selectivity for POE, with a linear response range of concentrations from 0.01 to 360 μM and a low detection limit (LDL) of 2.73 nM. The sensor also exhibited good stability and reproducibility, making it a promising tool for practical pesticide detection applications. The developed sensor offers a cost-effective, sensitive, and reliable platform for the rapid monitoring of organophosphate pesticides in environmental samples, contributing to the advancement of pesticide detection technologies and environmental protection efforts.

Comparative Analysis of Anisotropic Lipophilicity of a Series of 6-Chloro-1,3,5-Triazines Determined in Reversed Phase Ultra High Performance Liquid Chromatography System

Triazine derivatives are well-known commercially available compounds used for selective weed control in different crops, such as corn and sugarcane. Some of them are considered persistent organic compounds in the environment and it is important to improve the features of herbicide formulae, to estimate their physicochemical properties and to determine their retention behavior in modern analytical techniques that can be used in the determination of pesticides in environmental samples. The present study deals with a comprehensive analysis of the chromatographic behavior of a series of 6-chloro-1,3,5-triazines with alkyl and cycloalkyl substituents, among which some compounds possess herbicidal and fungicidal activity. The anisotropic lipophilicity of triazine derivatives was determined using reversed-phase ultra high performance liquid chromatography with octadecyl and phenyl columns and applying binary (methanol/water and acetonitrile/water) and ternary (methanol/acetonitrile/water) mobile phases under isocratic conditions. The retention data were analyzed using chemometric pattern recognition methods (hierarchical cluster analysis and principal component analysis) and sum of ranking differences method. The obtained results are excellent indicators of the retention behavior and the lipophilicity of the analyzed series of triazines and can serve as an outstanding basis for the development of new chromatographic methods for the determination of triazines in environmental samples.

A New Chemosensor Based on a Luminescent Complex for the Investigation of Some Organophosphorus Pesticides in Environmental Samples

Organophosphorus pesticides (OPPs) play a vital role in agriculture. However, their release into the environment can have serious repercussions. Therefore, the development of rapid and reliable methods for determining OPPs has received considerable attention in recent decades. Here, a new chemosensor based on a complex of vitamin B1 (vitB1) as a ligand with europium(III) ion, with a 1:2 stoichiometric ratio, was developed in solution to detect chlorfenvinphos and malathion in water samples using the luminescence method. The detection method is based on the luminescence quenching of a Eu(III)–vitamin B1 probe in solution upon increasing the concentration of chlorfenvinphos or malathion. The optimum solvent for the detection was methanol. The detection limits were 0.31 and 0.12 µM for chlorfenvinphos and malathion, respectively. According to the ratiometric method, malathion has a 13-fold higher binding affinity for the Eu(III)–(vitB1)2 complex than chlorfenvinphos. The reaction between the probe and OPPs under study was spontaneous and had a negative ΔG0. The method was successfully applied to determine chlorfenvinphos and malathion in three different water samples. Based on these studies, future work will be carried out to establish the optic fiber sensor.

Natural deep eutectic solvent-decorated magnetic layered double hydroxide as a sorbent for the enrichment of organochlorine pesticides in environmental samples

A newly designed magnetic layered double hydroxide composite modified with a natural deep eutectic solvent derived from choline chloride and sucrose was synthesized and applied as a sorbent for the enrichment of organochlorine pesticides. The magnetic solid phase extraction (MSPE) procedure was optimized via a small central composite design and response surface methodology. The MSPE method was able to preconcentrate the organochlorine residues in environmental samples prior to GC–MS analysis. Good analytical performance of the proposed method was observed with an enrichment factor of up to 158 and low limits of detection in the ranges of 0.002–0.015 µg·L−1 and 0.03–0.10 ng·g−1 for water and soil, respectively. Satisfactory recoveries for spiked water and soil samples were obtained in the ranges of 80.9–104.7% (RSDs<7.9) and 88.8–104.1% (RSDs<7.3), respectively. This finding highlights the role of natural deep eutectic solvents as modifying agents for magnetic layered double hydroxides, which enhance the efficiency of extraction of the target analytes. The developed MSPE/GC–MS procedure was sensitive and reliable for the determination of trace organochlorine residues in environmental samples.

A Cationic Surfactant-Decorated Liquid Crystal-Based Aptasensor for Label-Free Detection of Malathion Pesticides in Environmental Samples

We report a liquid crystal (LC)-based aptasensor for the detection of malathion using a cationic surfactant-decorated LC interface. In this method, LCs displayed dark optical images when in contact with aqueous cetyltrimethylammonium bromide (CTAB) solution due to the formation of a self-assembled CTAB monolayer at the aqueous/LC interface, which induced the homeotropic orientation of LCs. With the addition of malathion aptamer, the homeotropic orientation of LCs changed to a planar one due to the interactions between CTAB and the aptamer, resulting in a bright optical image. In the presence of malathion, the formation of aptamer-malathion complexes caused a conformational change of the aptamers, thereby weakening the interactions between CTAB and the aptamers. Therefore, CTAB is free to induce a homeotropic ordering of the LCs, which corresponds to a dark optical image. The developed sensor exhibited high specificity for malathion determination and a low detection limit of 0.465 nM was achieved. Moreover, the proposed biosensor was successfully applied to detect malathion in tap water, river water, and apple samples. The proposed LC-based aptasensor is a simple, rapid, and convenient platform for label-free monitoring of malathion in environmental samples.

Silver Nanoparticles with Sodium Dodecyl Sulfate as a Colorimetric Probe for the Detection of Dithiocarbamate Pesticides in Environmental Samples.

A rapid and simple colorimetric approach has been developed for sensing dithiocarbamate pesticides (ziram, zineb and maneb) in environmental samples using sodium dodecyl sulfate capped silver nanoparticles (SDS-AgNPs). They were characterized by a UV-vis spectrophotometer, FT-IR, SEM and EDX. Dithiocarbamates on interactions with SDS-AgNPs induce the aggregation of NPs, leading to a color change from yellow to greyish or dark brownish, depending on the concentration of pesticides added. A shift in the wavelength was observed from 400 to 570 nm with the broad band. The absorption ratio, 570/400 nm, was found to be linearly related to the concentration of pesticides in the range of 195.7 - 733.9 ng/mL for ziram, 17.6 - 66.2 ng/mL for zineb and 16.9 - 63.6 ng/mL for maneb with the detection limits of 149.3, 4.0 and 9.1 ng/mL for ziram, zineb and maneb, respectively. The method was successfully applied for the determination of DTCs in environmental samples (tap water, tomato, mango beverage) with percentage recoveries of 94.8 - 108.4% for ziram, 93.7 - 105.4% for zineb and 93.2 - 107.6% for maneb. The procedure was repeatable with inter-day RSD (n = 5) within 3.4, 4.8, 7.6% and intra-day RSD (n = 5) within 1.2, 1.7 and 1.8% for the ziram, zineb and maneb respectively.

Determination of pesticides using a low-temperature co-fired ceramic microfluidic platform

ABSTRACTThe aim of this work is the integration of an improved graphite–epoxy composite electrode modified with the acetylcholinesterase enzyme as a detector into a green tape ceramic microfluidic device for the online amperometric determination of pesticides. First, the operational conditions of the microfluidic system were optimized for the enzymatic substrate determination of acetylthiocholine. Good results were achieved for acetylthiocholine determination, obtaining a low detection limit and optimal sensitivity. The analytical performance of the microanalyzer was evaluated with organophosphorus and carbamate pesticides across a wide concentration range. Pesticides were determined indirectly measuring the enzymatic inhibition effect that they caused. The analysis was based on stopped-flow methodology with a three-step strategy: enzymatic substrate measurement, enzymatic inhibition by pesticide contact with the biosensor, and enzymatic substrate measurement after the inhibition process. The pesticide concentrations were determined by the percentage of inhibition produced. The microanalyzer was used for the analysis of spiked irrigation water samples using this indirect method. The low-temperature co-fired ceramic/epoxy–graphite–acetylcholinesterase microfluidic system showed low limits of detection and adequate sensitivity. The recoveries of the spiked water samples were approximately 100% with relative standard deviation values lower than 5% for three replicate measurements. All results obtained are indicative of a convenient, rapid, sensitive, and economic method for the determination of pesticides in environmental samples.

New High Throughput Microtiter Plates for Detection of Organophosphorous Pesticides in Environmental Samples.

New High Throughput Microtiter Plates for Detection of Organophosphorous Pesticides in Environmental Samples.

Press-transferred carbon black nanoparticles on board of microfluidic chips for rapid and sensitive amperometric determination of phenyl carbamate pesticides in environmental samples

The authors describe a strategy for rapid and sensitive determination of phenyl carbamate pesticides in environmental samples. It consists of the following steps: (a) Enrichment and clean-up of the analytes using a C18 microtip based procedure; (b) alkaline hydrolysis of the carbamates (carbofuran, isoprocarb and carbaryl) to form phenol derivatives; and (c) fast separation and amperometric detection in a microfluidic chip (MCs). The microchips were fabricated by using press-transferred carbon black nanoparticles (CB-NPs) as electrochemical sensing nanomaterial. The excellent electrochemical behavior of the CB-NPs coupled to the microchip warrants good separation and allows for the voltammetric determination (best at a working voltage of +0.70 V vs Ag/AgCl) of the carbamates within < 6 min. The authors also describe a rapid procedure for the clean-up and enrichment of the carbamates from real samples by using a C18 microtip. The procedure allowed a 10-fold enrichment of the analytes, and this led to a detection limits in the 0.7 to 1.2 μM concentration range. The assay was applied to samples of river, lake and irrigation water that were spiked with carbamates at 50 and 100 μM levels. Recoveries are in the 87 to 108 % range, and RSDs (n = 3) in the 5 to 11 % range. The exploitation of the such nanomaterials coupled to microfluidics and microextraction procedures for real sample analysis in our preception represents a most viable tool for the analysis of complex real samples, for on-site environmental monitoring, and for rapid diagnosis.

ASSESSMENT OF PESTICIDES IN ENVIRONMENTAL SAMPLES USING VOLTAMMETRIC MOLECULAR IMPRINTED BASED SENSORS: A REVIEW (2006-2015)

The increased concerns about toxic effects of pesticides exposure led to necessity of its monitoring using rapid, sensitive and selective analytical tools. Traditional instrumental analytical techniques are often time consuming, labor intensive and need tedious prior separation or purification steps and expensive instrumentation. Besides those electrochemical sensors can overcome disadvantages of the traditional techniques, MIP-based sensors offer high degree of selectivity in binding target analytes in the presence of their interferents making them ideal for determination of pesticides in complex environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first methods of MIP preparation and then dealing with applications of MIP based sensors in assessment of pesticides in environmental samples using voltammetry as transduction mechanism.

Recent Advances in the Determination of Pesticides in Environmental Samples by Capillary Electrophoresis.

Nowadays, owing to the increasing population and the attempts to satisfy its needs, pesticides are widely applied to control the quantity and quality of agricultural products. However, the presence of pesticide residues and their metabolites in environmental samples is hazardous to the health of humans and all other living organisms. Thus, monitoring these compounds is extremely important to ensure that only permitted levels of pesticide are consumed. To this end, fast, reliable, and environmentally friendly methods that can accurately analyze dilute, complex samples containing both parent substances and their metabolites are required. Focusing primarily on research published since 2010, this review summarizes the use of various sample pretreatment techniques to extract pesticides from various matrices, combined with on-line preconcentration strategies for sensitivity improvement, and subsequent capillary electrophoresis analysis.

New High Throughput Microtiter Plates for Detection of Organophosphorous Pesticides in Environmental Samples

Quenching of lanthanides luminescence of a novel long live Tb(III)- Ethyl 1-allyl-1,2-dihydro-4-hydroxy-2-oxoquinoline-3-carboxylate (EADHOC) as a ligand to form a complex with molar ratio 1:3 in solution has been studiedin ethanol in presence of organophosphorus pesticides both Di-chlorvos (P1) and paraoxon-Ethyl (P2). The intensity ofluminescence of Tb(III) –(EADHOC) decrease as the concentration of pesticides increase. The quenching effect wasobserved with both pesticides. Direct methods of determination of pesticides under investigated have been developed byusing luminescence of Tb(III) –(EADHOC) probe in a solution. The linear range for determination of the selectedpesticides P1(Di-chlorovos) and P2(Paraoxon-Ethyl) is 7 and 1 μM. the detection limits were 1.9 and 9.8 μM for P1(Dichlorovos)and P2 (Paraoxon-Ethyl) respectively. The Thermodynamic parameters and binding constant (K) of OPswith Tb(III) – (EADHOC) were evaluated. Including the value of enthalpy (ΔH ) and entropy( ΔS ) changes for Probeinteraction with pesticides. As the natural water sample in this study don't contain the above mentioned OPs over thelimit detected by the methods, a recovery study was carried out after the addition of the adequate amount oforganophosphorus pesticides under investigation.

Remediation of hexachlorocyclohexanes by cobalt-mediated activation of peroxymonosulfate

Hexachlorocyclohexane isomers (HCHs) are one of the most ubiquitous and most easily detected organochlorine pesticides in environmental samples. This global distribution is enabled by HCH persistence. Moreover, HCH tends to bioaccumulate in human and animal adipose tissue. Since certain HCHs cause central nervous system, reproductive, and other endocrine damages, there is a necessity of a suitable remediation method to remove HCH from contaminated groundwater and soil. This study was conducted to evaluate the potential of peroxymonosulfate (Oxone) induced by cobalt salt (Co(NO3)2; Co(II)) to degrade HCHs. Cobalt(II) nitrate has been chosen instead of cobalt(II) chloride (which presents better activation properties for Oxone) in order to avoid an excess of chloride interference and more additional chlorination by-products. The optimal conditions (oxidant dose as well as cobalt dose) were determined for spiked water with HCH (0.85 μM of summed HCH isomers). Optimal oxidant dose was established by running a test with three different Oxone concentrations (molar ratio of Oxone:Co(NO3)2—1:0.1): 0.06, 0.6, and 6 mM. Degradation curves of summed HCH isomers were fitted into the pseudo-first-order kinetic model, and reaction rates are shown to be 0.03, 0.31, and 0.55 min−1 for doses 0.06, 0.6, and 6 mM, respectively. Further experiments were carried out to determine the optimal Oxone:Co(NO3)2 molar ratio. Effectiveness of HCHs decontamination by Oxone:Co(NO3)2 in various molar ratios was in the order 1:0.1 > 1:1 > 1:0.01 > 1:0.001. It was observed that surplus of Co(NO3)2 can slow down the degradation rate constants. A reaction between sulfate radicals and Co(NO3)2 could be responsible for this phenomenon, which can lead to the formation of sulfate ions without HCHs oxidation. In addition, tests with higher HCH dose (close to the solubility limit) were carried out to determine by-products of decontamination. In these tests 2,4,6-trichlorophenol (2,4,6-TCP) was found to be the major intermediate of HCH isomers degradation. Trace levels of the trichlorobenzene (TCB), tetrachlorophenol (TeCP), and pentachlorophenol (PCP) were detected as well. The study revealed that Oxone induced by Co(II) shows a high degradation rate with HCH isomers, which can make it an attractive method for HCHs decontamination in the future.

Development of Immunochromatographic Assay for Identification of Organophosphate Pesticides in Environmental Samples

Microtiter plate enzyme linked immunoassay (ELISA) experiments in competitive format were performed utilizing polyclonal antibody for establishing a detection system for organophosphate pesticides. IC50 value of and limit of detection (LOD) value was determined by standard inhibition curve and value obtained were 0.05 μgmL−1 and 0.001 μgmL−1, respectively. Specificity of antibody was investigated with different organophosphate pesticides. Immunochromatographic assay (ICA) experiments were also designed in competitive format by making use of immunochromatographic strip which was assembly of three main components: conjugate pad, membrane and adsorbent pad. Membrane was coated with hapten-OVA conjugate (test line) and antirabbit IgG (control line). ICA experiments were performed by employing gold-labeled antibody as a detector reagent which was applied over conjugate pad. Visual detection limit obtained from ICA was 0.5 μgmL−1. Major advantage of strip assay was rapid result, i.e., less than 10 min. which makes it suitable for onsite applications.

Two dispersive liquid–liquid microextraction methods coupled with gas chromatography–mass spectrometry for the determination of organophosphorus pesticides in field water

Environmental context Conventional sample pretreatment for the determination of pesticides in environmental samples is time consuming and labour intensive. We report two dispersive liquid–liquid micro-extraction methods that provide rapid homogeneous emulsification in aqueous samples within 2min. These simple and environmentally friendly extraction methods are particularly suitable for the measurement of organophosphorus pesticides in field water. Abstract The methods up-and-down shaker-assisted dispersive liquid–liquid microextraction (UDSA-DLLME) and water with low concentration of surfactant in dispersed solvent-assisted emulsion dispersive liquid–liquid microextraction (WLSEME) were developed for the analysis of 13 organophosphorus pesticides (OPPs) in water samples by gas chromatography–mass spectrometry (GC-MS). UDSA-DLLME required only 14μL of 5-methyl-1-hexanol as the extraction solvent. The use of an up-and-down shaker allowed homogeneous and rapid emulsification of aqueous samples. OPP extraction was completed in 2min. In WLSEME, a mixture containing 9μL of the extraction solvent (1-heptanol) and 250μL of water as the dispersed solvent (containing 10mgL–1, Triton X-100) was withdrawn and expelled four times within 10s using a microsyringe to form a cloudy emulsion in the syringe. This emulsion was then injected into 5mL of aqueous sample spiked with all of the above OPPs. The total extraction time was ~0.5min. After optimisation, the linear range of the method was 0.1–100μgL–1 for UDSA-DLLME and 0.05–100μgL–1 for WLSEME. The coefficient of determination was greater than 0.9958. The limits of detection ranged from 0.040 to 0.069μgL–1 for UDSA-DLLME and 0.020 to 0.035μgL–1 for WLSEME. Analyses of river water, lake water and underground water had absolute recoveries of 34 to 96% and relative recoveries of 84 to 115% for both methods. Other emulsification methods such as vortex-assisted, ultrasound-assisted and manual-shaking-enhanced ultrasound-assisted methods were also compared against the proposed UDSA-DLLME and WLSEME methods. The results reveal that UDSA-DLLME and WLSEME provided higher extraction efficiency and precision.

Single Drop Microextraction: a Sensitive Multiresidue Method for Determination of Pesticides in Water Using GC/ECD

The monitoring of pesticides in environmental samples at low concentrations is needed due to the risks that these compounds can pose to human health and the environment. In this work, a single drop microextraction (SDME) method was optimized and validated for the determination of trace concentrations of eight pesticides in water, using gas chromatography with electron capture detector (GC/ECD). The kinetics of the transfer of material from the aqueous phase to the organic phase during the extraction process was also evaluated. The method showed recoveries between 89.5 and 122.7%, with coefficients of variation smaller than 22.9%, and detection limits between 5.9 and 58.9 ng L-1. The method was applied to spiked samples at different concentration levels, and recoveries between 50.5 and 148% were obtained. The extraction process could be described by the Noyes-Whitney diffusion model, and methyl parathion showed the highest rate of transfer between the two phases.

GC-MS Determination of Targeted Pesticides in Environmental Samples from the Kafue Flats of Zambia

Results of a GC-MS analysis for targeted pesticides i.e. dieldrin, endosulfan, pp-DDT, endrin, HCB, heptachlor, mirex and aldrin in the Kafue Flats of Zambia are presented. Analysis was done in soils, sediments, water and vegetation samples from the Lochinvar and Blue Lagoon National Parks along the Kafue River. A validated analytical method that was used gave recoveries in a spiked soil sample ranging between 60 % and 100 % with limits of detection (LODs) ranging from 0.94 to 8.0 ng/g. The targeted pesticides were not detected in all the samples i.e. were below LODs. Screening using the Automated Mass Spectral Deconvolution and Identification System (AMDIS) simplified the analysis due to its power of deconvolution and identification of analytes of interest.

Determination of pyrethroid pesticides in environmental samples using ionic liquid dispersive liquid-liquid microextraction

Dispersive liquid-liquid microextraction (DLLME) using ionic liquid (IL) as extraction solvent was developed as a new approach for the determination of four pyrethroid pesticides in environmental water and soil samples. High-performance liquid chromatography with ultraviolet detection (HPLC-UV) was employed on chromatographic analysis. The method is rapid, easy to operate and enviromentally-friendly. The highly toxic chlorinated solvent was replaced by the IL 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]), in which high extraction recovery and enrichment factors were obtained. The effects of IL volume, type and volume of disperser solvent, salt addition, pH and extraction time were investigated and optimized. Under optimum conditions, the method showed good linear response with correlation coefficient (R²) values in the range of 0.9943 to 0.9986. Relative standard deviation (RSD) varied from 3.9 to 10.1%. Enrichment factor, limit of detection and recovery ranged from 260 to 319, 0.94 to 1.97 µg L-1 and 89 to 98%, respectively. For real water samples, RSD ranged from 3.8 to 10.8%, and recovery from 83 to 99%. For soil sample analysis, RSD and recovery ranged from 3.7 to 8.9% and 88 to 98, respectively.

In-situ metathesis reaction combined with ultrasound-assisted ionic liquid dispersive liquid–liquid microextraction method for the determination of phenylurea pesticides in water samples

A novel microextraction technique, named in-situ metathesis reaction, combined with ultrasound-assisted ionic liquid dispersive liquid–liquid microextraction was developed for the determination of five phenylurea pesticides (i.e., diuron, diflubenzuron, teflubenzuron, flufenoxuron, and chlorfluazuron) in environmental water samples. In the developed method, 360μL LiNTf2 aqueous solution (0.162g/mL) was added to the sample solution containing a small amount of [C6MIM]Cl (0.034g) to form a water-immiscible ionic liquid, [C6MIM]NTf2, as extraction solution. The mixed solutions were placed in an ultrasonic water bath at 150W for 4min and centrifuged at 3500rpm for 10min to achieve phase separation. After centrifugation, fine droplets of the extractant phase settled to the bottom of the centrifuge tube and were directly injected into the high-performance liquid chromatography system for analysis. The quantity of [C6MIM]Cl, the molar ratio of [C6MIM]Cl and LiNTf2, ionic strength, ultrasound time, and centrifugation time, were optimized using a Plackett–Burman design. Significant factors obtained were optimized by employing a central composite design. The optimized technique provides good repeatability (RSD 2.4 to 3.5%), linearity (0.5μg/L to 500μg/L), low LODs (0.06μg/L to 0.08μg/L) and great enrichment factor (244 to 268). The developed method can be applied in routine analysis for the determining of phenylurea pesticides in environmental samples.