Simultaneous Determination Of Organophosphorus Pesticides Research Articles

Analytical Extraction Methods and Sorbents' Development for Simultaneous Determination of Organophosphorus Pesticides' Residues in Food and Water Samples: A Review.

Extensive use of organophosphorus pesticides in agriculture leads to adverse effects to the environment and human health. Sample preparation is compulsory to enrich target analytes prior to detection as they often exist at trace levels and this step is critical as it determines the concentration of pollutants present in samples. The selection of a suitable extraction method is of great importance. The analytical performance of the extraction methods is influenced by the selection of sorbents as sorbents play a vital role in the sensitivity and selectivity of an analytical method. To date, numerous sorbent materials have been developed to cater to the needs of selective and sensitive pesticides’ detection. Comprehensive details pertaining to extraction methods, developed sorbents, and analytical performance are provided. This review intended to provide a general overview on different extraction techniques and sorbents that have been developed in the last 10 years for organophosphorus pesticides’ determinations in food and water samples.

Solid-phase extraction using chloropropyl functionalized sol-gel hybrid sorbent for simultaneous determination of organophosphorus pesticides in selected fruit samples.

A new sol-gel hybrid methyltrimethoxysilane-chloropropyltriethoxysilane was prepared as sorbent for solid-phase extraction. The extraction efficiency of the prepared sol-gel hybrid methyltrimethoxysilane-chloropropyltriethoxysilane was assessed by using three selected organophosphorus pesticides, namely, chlorpyrifos, profenofos, and malathion. Gas chromatography-mass spectrometry was used for detection of organophosphorus pesticides. Several vital parameters were optimized to identify the best extraction conditions. Under the optimum extraction conditions, solid-phase extraction-methyltrimethoxysilane-chloropropyltriethoxysilane method showed good linearity range (0.05-1μg/mL) with coefficient of determination more than 0.995. The limits of detection obtained were in the range of 0.01-0.07μg/mL and limits of quantification ranging from 0.03 to 0.21μg/mL. The limits of detection obtained for the developed method were 2.3-6.5× lower than the limits of detection of commercial octadecyl silica sorbent. Real samples analysis was carried out by applying the developed method on red apple and purple grape samples. The developed method exhibited good recoveries (88.33-120.7%) with low relative standard deviations ranging from 1.6 to 3.3% compared to commercial octadecyl silica sorbent, which showed acceptable recoveries (70.3-100.2%) and relative standard deviations (6.3-8.8%). The solid-phase extraction-methyltrimethoxysilane-chloropropyltriethoxysilane method is presented as an alternative extraction method for determination of organophosphorus pesticides.

Simultaneous determination of organophosphorus pesticides in fruits and vegetables using atmospheric pressure gas chromatography quadrupole-time-of-flight mass spectrometry

This paper describes the application of atmospheric pressure gas chromatography quadrupole-time-of-flight mass spectrometry for the simultaneous determination of organophosphorus pesticides in apple, pear, tomato, cucumber and cabbage. Soft ionization with atmospheric pressure ionization source was compared with traditional electron impact ionization (EI). The sensitivity of GC coupled to atmospheric pressure ionization (APGC) for all the analytes was enhanced by 1.0–8.2 times. The ionization modes with atmospheric pressure ionization source was studied by comparing the charge-transfer and proton-transfer conditions. The optimized QuEChERs method was used to pretreat the samples. The calibration curves were found linear from 10 to 1000μg/L, obtaining correlation coefficients higher than 0.9845. Satisfactory mean recovery values, in the range of 70.0–115.9%, and satisfactory precision, with all RSDr <19.7% and all RSDR values <19.5% at the three fortified concentration levels for all the fifteen OPPs. The results demonstrate the potential of APGC-QTOF-MS for routine quantitative analysis of organophosphorus pesticide in fruits and vegetables.

Development of a one-step microwave-assisted extraction method for simultaneous determination of organophosphorus pesticides and fungicides in soils by gas chromatography–mass spectrometry

A one-step microwave-assisted extraction (MAE) procedure was developed for the simultaneous extraction of organophosphorus pesticide and fungicide residues in soil which have been greatly used in agriculture. Parameters that could influence the MAE efficiency such as irradiation power, temperature, time and solvent were investigated, and extraction efficiencies in the range of 92.6−103.7% were obtained using 400W (100% output) at 160°C for 10min with only 12mL of acetone–hexane (2:1, v/v). The analytes in extracts were analyzed directly by gas chromatography–mass spectrometry (GC–MS) without any further cleanup. At 5 and 50ngg−1 fortification levels for each analyte, the average recoveries obtained were ranged from 70.0% to 120.0% with relative standard deviation (RSD) between 0.2% and 14%. The method was linear over 1–250ngg−1 with a correlation coefficient (r2) between 0.9916 and 0.9966. The detection limits (S/N=3) were between 0.10 and 0.12ngg−1. The applicability of the method was demonstrated by analyzing field soil samples collected from six intensive horticultural sites in Ethiopia.

A simple, rapid and high-throughput fluorescence polarization immunoassay for simultaneous detection of organophosphorus pesticides in vegetable and environmental water samples

A simple, rapid and high-throughput fluorescent polarization immunoassay (FPIA) for simultaneous determination of organophosphorus pesticides (OPs) using a broad-specificity monoclonal antibody was developed. The effects of tracer structure, tracer concentration, antibody dilution, methanol content and matrix effect on FPIA performance were studied. The FPIA can detect 5 OPs simultaneously with a limit of detection below 10 ng mL −1. The time required for the equilibrium of antibody–antigen interaction was less than 10 min. The recovery from spiked vegetable and environmental samples ranged from 71.3% to 126.8%, with the coefficient of variations ranging from 3.5% to 14.5%. The developed FPIA was applied to samples, followed by confirmation with high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) analysis. The developed FPIA demonstrated good accuracy and reproducibility, and is suitable for rapid and high-throughput screening for OP contamination with high-efficiency and low cost.

Simultaneous determination of organophosphorus pesticides in Chinese herbal medicines by microwave‐assisted extraction coupled with dispersive‐solid phase extraction and gas chromatography

A reliable, rapid and nontoxic analytical method was proposed for the simultaneous determination of 16 organophosphorus pesticides in Chinese herbal medicines. The pesticides were extracted by ethanol and the experimental variables, such as temperature, extraction time and volume of ethanol, were optimized through orthogonal array experimental design. Cleanup of extracts was performed with dispersive-solid phase extraction using primary secondary amine as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography-flame photometric detection. Under optimized conditions the obtained recoveries, except for isocarbophos, were in the range 73.8-123%, with relative standard deviations equal to or lower than 15.2% and limits of detection ranging from 0.001 to 0.009 mg/kg.

Rapid simultaneous determination of organophosphorus pesticides in human serum and urine by liquid chromatography-mass spectrometry

Analysis of organophosphosphorus compounds and their metabolites in a biological material includes the use of numerous methods, covering both preparation of samples for analysis and their identification that is considered to be very complex. Low concentrations monitoring requires implementation of highly sensitive analytical techniques. The aim of this study was to develop and validate an original and sensitive method for the detection and quantitation of organophosphorus pesticides (dimethoate, diazinon, malathion and malaoxon) in human biological matrices (serum, urine). This method was based on a solid-phase extraction procedure, a chromatographic separation using an ACQUITY UPLC HSST3 column and mass spectrometric detection in the positive ion mode. Mobile phase: was consited of Solvent A (5 mM ammonium formate pH 3.0) and Solvent B (0.1% acetic formate in methanol), in a linear gradient (constant flow-rate 0.3 mL/min). The standard curve was linear in the range of 0.05-5.00 mg/L for malathion and malaoxon, 0.10-5.00 mg/L for dimethoate and 0.05-2.50 mg/L for diazinon. The correlation coefficient was r > or = 0.99. Extraction recoveries were satisfactory and ranged between 90-99%. The limits of detection (LOD) was between 0.007-0.07 mg/L and the limits of quantitation (LOQ) ranged between 0.022-0.085 mg/L. Intra- and interassay precision and accuracy were satisfactory for all of the pesticides analyzed. The method of liquid chromatography-mass spectrometry is simple, accurate, and useful for the determination of organophosphorus pesticides in both clinical and forensic toxicology.

Simultaneous determination of organophosphorus pesticides in cruciferous vegetables by dual-column GC with pulsed FPD and FTD

We evaluated simultaneous analytical methods for organophosphorus pesticides in cruciferous vegetables by gas chromatography (GC). Firstly, 36 pesticides were selected on the basis of monitoring data (April 1996-March 2003) in Aichi Prefecture. A sample was extracted with acetonitrile and the acetonitrile layer was separated by salting-out. The extract was cleaned up with gel permeation chromatography (GPC), and then with a tandem silica-gel/PSA mini-column. The test solution was subjected to dual-column GC equipped with a pulsed FPD (P mode, Rtx-OPPesticides column) and a FTD (Rtx-OPPesticides 2 column). Organophosphorus pesticides in such sulfur-rich matrices as cabbage and radish were determined without any serious interfering peaks on the pulsed FPD chromatograms after diluting the extracts 10- to 20-fold (0.25-0.5 mg/L of sample). The method was applied to cruciferous vegetables to demonstrate its usefulness in routine analysis.

Multiresidue determination of persistent organochlorine and organophosphorus compounds in whale tissues using automated liquid chromatographic clean up and gas chromatographic–mass spectrometric detection

A multiresidue method based on normal-phase LC for the sample clean up of whale tissues extracts prior to GC–MS determination of residues of polychlorinated biphenyls, organochlorine pesticides and derivatives and lipophylic organophosphorus pesticides has been developed. Pesticides were extracted from blubber by fusing and dissolving the fat in n-hexane and from liver and kidney by reflux in n-hexane. Hexanic extracts were directly injected on the silicagel column of the automated LC clean up system, using n-hexane as mobile phase. Diode array detection allowed the on-line monitoring of lipids elution from the LC system. Purified extracts were analysed by GC using mass selective detection. The developed procedure was applied to different tissues from a whale specimen appeared in the Valencian coast, finding high concentrations of OCs (up to 7.3 μg g −1 pp’-DDE, and 7.2 μg g −1 PCBs). The method was validated by means of recovery tests for all the compounds detected in the whale and also for some other OCs and OPs studied in this paper. The method improves other current methods for the analysis of persistent organochlorines in marine mammals with regard to time of analysis, solvent expend and automation; solvent exchanges are not necessary before GC analysis, and it allows the simultaneous determination of organophosphorus pesticides.

Rapid and Simultaneous Determination of Organophosphorus Pesticides in Agricultural Products by FPD-GC

A method for rapid and simultaneous determination of 19 kinds of organophosphorus pesticides was developed by FPD-GC with two kinds of capillary columns (DB-5MS and DB-210). Sample preparation of the 19 pesticides in agricultural products was systematically established as follows. 1) Pesticides in vegetables and fruits were extracted with acetone, re-extracted with dichloromethane, and determined by GC. 2) Pesticides in onion were extracted with acetone by homogenation of a frozen sample in dilute phosphoric acid, and re-extracted with dichloromethane. 3) Pesticides in soybean, redbean and hulled rice were extracted with 30% aqueous acetone, then cleaned up with zinc acetate in order to remove some of the components, including fatty acids, as a precipitate, and re-extracted with dichloromethane. 4) Pesticides in green tea were extracted and re-extracted by the same method as in 3). Then the dichloromethane extract was concentrated to dryness, and the residue obtained was extracted with n-hexane in order to remove insoluble components.Recoveries and coefficients of variation of the pesticides in all agricultural products were in the ranges of 46.7-120% and 0.1-14.9%, respectively.

Simultaneous determination of organophosphorus pesticides by thin-layer chromatography.

Normal phase and reversed-phase thin-layer chromatographic (NP-and RP-TLC) methods were developed for the simultaneous determination of 45 organophosphorus pesticides (OP ; 8 phosphates, 14 phosphorothioates, 15 phosphorodithioates and 8 miscellaneous OP), which were used or had been used in Japan. The pesticides were analysed by three TLC systems by using Merck Silica gel 60 F-254 plate (n-hexane-acetone 7 : 3, v/v) and Merck RP-8F254 s and Whatman KC18F plates (methanol-water 7 : 3, v/v). The locations of the pesticides were detected by UV absorption and by colorations with palladium chloride and 4-(p-nitrobenzyl)pyridine (NBP). All of the pesticides tested could be detected with the NBP reagent, and its detection limit was less than 0.25-0.5μg of OP except 1μg of trichlorfon. The most effective discriminating powers (DP) for TLC analyses of OP were given by the combination of two TLC systems with silica gel and chemical bonded silica gels (DP=0.93 and 0.94, numbers of samples 45, and error factor 0.05). Together with our previous papers on analyses of OP by gas-liquid chromatography and directinlet and gas-chromatography-mass spectrometry (DI-and GC-MS), the most reliable procedure proposed for the examination of OP is as follows. At first, samples are applied to the TLC analyses for the screening test of OP, and then the pesticides are identified with GC-MS on column of OV-1 or QF-1 and/or DI-MS.