Concentrations Of Parathion Research Articles

Adsorption and degradation of methyl parathion (MP), a toxic organophosphorus pesticide, using NaY/Mn0.5Zn0.5Fe2O4 nanocomposite

In this research, the applicability of NaY/Mn0.5Zn0.5Fe2O4 as a new synthesized nanocomposite adsorbent for the adsorption and degradation of methyl parathion (MP, O,O-dimethyl O-p-nitrophenyl phosphorothioate), an organophosphorus pesticide, is investigated. IThe prepared samples were characterized via SEM-EDAX, TEM, XRD, FTIR, VSM and N2-BET techniques. The role of several experimental factors such as contact time, adsorbent dose and initial concentration of methyl parathion on the removal efficiency of this pesticide were considered and evaluated via 31P nuclear magnetic resonance (31PNMR) spectroscopy. 31PNMR spectroscopy showed that methyl parathion was desirably removed by the NaY/Mn0.5Zn0.5Fe2O4 nanocomposite with a yield of more than 90% under certain optimized conditions. Factors including contact time (80 min), adsorbent dose (0.5 g), and initial pesticide concentration (15 mg/L) were studied and optimized for the reaction. Reaction kinetic status was surveyed using a first order model. The values of the half-life (T 1/2) and rate constant (k) were 54.6 min and 0.0127 min−1, respectively. The products of the degradation reaction between methyl parathion and NaY/Mn0.5Zn0.5Fe2O4 were dimethyl phosphorothioic acid (DMPA) and p-nitrophenol (PNP), which are significantly less toxic than the primary pesticide.

Nanocomposites composed of layered molybdenum disulfide and graphene for highly sensitive amperometric determination of methyl parathion

The authors describe an inexpensive electrode for the sensitive amperometric determination of the pesticide methyl parathion. A glassy carbon electrode was modified with a nanocomposite consisting of molybdenum disulfide nanosheets (MoS2) and graphene that was prepared via a hydrothermal process. Its morphology, elemental composition, diffraction, impedance and voltammetric characteristics were studied. The modified electrode displays excellent electrocatalytic ability towards methyl parathion, and the reduction peak current, measured typically at −0.60 V (vs. Ag/AgCl) is related to the concentration of methyl parathion. The effect of concentration, scan rate and solution pH value were optimized. The calibration plot is linear in the 10 nM to 1.9 mM concentration range, with a 3.2 nM detection limit (at a signal-to-noise ratio of 3). The electrode is selective, stable, adequately repeatable and reproducible. The method was successfully applied to the determination of methyl parathion in spiked samples of homogenized apple, kiwi, tomato and cabbage.

A methyl parathion electrochemical sensor based on Nano-TiO2, graphene composite film modified electrode

ABSTRACTA methyl parathion electrochemical sensor based on nano-TiO2 and graphene composite film modified glassy carbon electrode has been developed. The electrochemical behavior of MP at the sensor was investigated by cyclic voltammetry and linear sweep voltammetry. Scanning electron microscopy was used to characterize the surface morphology of nano-TiO2 and graphene composite film. Compared with a bare glassy carbon electrode or a mono-film modified electrode, the redox peak currents of methyl parathion on the composite film modified electrode improved greatly, indicating that the sensor showed good catalytic effects. The optimal experimental condition was obtained. The results indicated that the linear sweep voltammetry responses of methyl parathion, in pH 5.2 acetate buffer solution with open-circuit accumulation for 2 min, were linear with concentrations of methyl parathion in two ranges of 0.002∼5 μM and 5∼100 μM. The linear equations were iPc(μA) = 0.0136 + 4.965cMP(μM) (R12 = 0.9911) and iPc(μA) = 21.87 + 0.8206cMP(μM) (R22 = 0.9914), respectively. The detection limit was 1.0 nM (S/N = 3). The sensor exhibited high sensitivity and good reproducibility as well as certain anti-interference ability. It was applied to the determination of residual MP in fresh apple sample with the recovery of 92%∼102%. The result was satisfactory.

Biotransformation of methyl parathion by marine-derived fungi isolated from ascidian Didemnum ligulum

Abstract This paper describes the biotransformation of methyl parathion by marine-derived fungi isolated from ascidian Didemnum ligulum. Seventeen strains were screened by their growth in solid culture medium containing different concentrations of methyl parathion (120 mg L −1 , 240 mg L −1 and 360 mg L −1 ). Three strains with potential to degrade methyl parathion were identified as Penicillium citrinum (DL4M3), P. citrinum (DL9M3) and Fusarium proliferatum (DL11A). When selected for experiments in liquid medium to quantify the biodegradation of methyl parathion, they were able to completely degrade it in 20 d. However, when comparing the hydrolysis of methyl parathion catalyzed by fungi with the chemical hydrolysis (abiotic control), there was no significant differences in the disappearance of the pesticide in both reactions. On the other hand, F. proliferatum DL11A strain was able to reduce the concentration of p -nitrophenol, the main metabolite of methyl parathion hydrolysis, promoting 90% of biodegradation/bioconjugation of p -nitrophenol in 30 d.

Silver nanoparticle-modified electrode for the determination of nitro compound-containing pesticides.

This paper reports the electroanalytical determination of pendimethalin and ethyl parathion by square-wave adsorptive stripping voltammetry using a material comprised of chitosan-stabilized silver nanoparticles to modify a glassy carbon electrode. Under optimized experimental conditions, the peak current was found to vary linearly with the concentration of pendimethalin in the range of 70 to 2000nmolL(-1) and with concentration of ethyl parathion in the range of 40 to 8000nmolL(-1). Detection limits of 36 and 40nmolL(-1) were obtained for pendimethalin and ethyl parathion, respectively. The silver - nanoparticle-modified electrode was successfully employed for the analysis of pesticides in tap and mineral water (pendimethalin) and in lettuce and honey (ethyl parathion) samples. Pendimethalin recovery was between 94 and 100%, and ethyl parathion recovery was between 97 and 101%, indicating no significant matrix interference effects on the analytical results. The accuracy of the electroanalytical methodology using the proposed modified electrode was also compared to that of the UV-vis spectrophotometric method.

Effects of GST Polymorphism on Ameliorative Effect of Curcumin and Carvacrol against DNA Damage Induced by Combined Treatment of Malathion and Parathion

Background: Organophosphorus pesticides has been widely used in agriculture fields to control various crop insects and their extensive use pose human life at threat because of their adverse effects on human health. In this study, we checked the effects of GST polymorphism on ameliorative effect of curcumin and carvacrol against DNA damages. Methods: Comet assay was used to assess the DNA damage and results were expressed as Tail moment. Heparinised fresh blood from healthy individuals was treated with combined concentration of malathion and parathion (i.e. 30 µg/ml of malathion and 2.5 µg/ml of parathion) in presence of combination of curcumin and carvacrol (25 µg/ml curcumin + 2.5 µg/ml carvacrol and 50 µg/ml curcumin + 5.0 µg/ml carvacrol) in order to observe the ameliorative role of curcumin and carvacrol. Multiplex PCR was performed for GSTM1 and GSTT1 genotyping. Results: Curcumin in combination with carvacrol (i.e. 25 µg/ml curcumin + 2.5 µg/ml carvacrol and 50 µg/ml curcumin + 5.0 µg/ml carvacrol) significantly reduced the DNA damage caused by combined action of malathion and parathion which supports their antigenotoxic property. No significant relationship of GSTT1 and GSTM1 polymorphism with genotoxicity of both the pesticides and antigenotoxic potential of curcumin and carvacrol was observed. Conclusion: Malathion and parathion were genotoxic in human PBL. Curcumin and carvacrol had an antigenotoxic effect against the malathion and parathion while there was not any significant effect of GSTT1 and GSTM1 polymorphism on genotoxicity of these pesticides and antigenotoxicity of curcumin and carvacrol.

Environmentally-friendly in situ plated bismuth-film electrode for the quantification of the endocrine disruptor parathion in skimmed milk

An in situ bismuth-film electrode (BiFE) together with square-wave cathodic voltammetry (SWCV) was used to determine the concentration of the endocrine disruptor parathion in skimmed milk. The experimental conditions (deposition time, deposition potential and Bi (III) concentration) were optimized for the preparation of the BiFE. A glassy carbon electrode was used as the substrate. The selection of the chemical composition of the supporting electrolyte and the solution pH was aimed at improving the reduction of parathion at the BiFE surface. In addition, the parameters of the square-wave cathodic voltammetry were adjusted to improve the sensor performance. A cathodic current identified at −0.523V increased linearly with the parathion concentration in the range of 0.2–2.0μmolL−1 (R=0.999). The sensitivity of the calibration curve obtained was 4.09μALμmol−1, and the limits of detection (LOD) and quantification (LOQ) were 55.7nmolL−1 and 169.0 nmolL−1, respectively. The performance of the sensor was tested using a sample of skimmed milk with parathion added. The same determination was carried out by UV–vis spectroscopy and the results obtained were used for the statistical evaluation of the data obtained.

Chemotaxis and degradation of organophosphate compound by a novel moderately thermo-halo tolerant Pseudomonas sp. strain BUR11: evidence for possible existence of two pathways for degradation.

An organophosphate (OP) degrading chemotactic bacterial strain BUR11 isolated from an agricultural field was identified as a member of Pseudomonas genus on the basis of its 16S rRNA gene sequence. The strain could utilize parathion, chlorpyrifos and their major hydrolytic intermediates as sole source of carbon for its growth and exhibited positive chemotactic response towards most of them. Optimum concentration of parathion for its growth was recorded to be 200 ppm and 62% of which was degraded within 96 h at 37 °C. Growth studies indicated the strain to be moderately thermo-halo tolerant in nature. Investigation based on identification of intermediates of parathion degradation by thin layer chromatography (TLC), high performance liquid chromatography (HPLC), gas chromatography (GC) and liquid chromatography mass spectrometry (LC-MS/MS) provided evidence for possible existence of two pathways. The first pathway proceeds via 4-nitrophenol (4-NP) while the second proceeds through formation of 4-aminoparathion (4-APar), 4-aminophenol (4-AP) and parabenzoquinone (PBQ). This is the first report of chemotaxis towards organophosphate compound by a thermo-halo tolerant bacterium.

Electrochemical preparation of a novel type of C-dots/ZrO2 nanocomposite onto glassy carbon electrode for detection of organophosphorus pesticide

A selective, sensitive novel electrochemical sensor for detection of methyl parathion on the preparation of a carbon dots (C-dots)/ZrO2 nanocomposite was developed. The C-dots/ZrO2 nanocomposite was fabricated using electrochemical deposition onto a glassy carbon electrode and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and cyclic voltammetry. The optimum parameters such as effect of pH, accumulation time, accumulation potential, scan rate, effect of amount of C-dots and effect of amount of ZrO2 were investigated. The C-dots/ZrO2 modified glassy carbon electrode allowed rapid, selective determination of methyl parathion in rice samples by adsorptive stripping voltammetry. The stripping response was highly linear over the methyl parathion concentrations ranging from 0.2ngmL−1 to 48ngmL−1, with a detection limit of 0.056ngmL−1. This novel electrochemical nanocomposite-based electrochemical sensor was successfully applied for the detection of methyl parathion in rice samples.

Pesticide residue in water--a challenging task in India.

Modern agriculture practices reveal an increase in use of pesticides to meet the food demand of increasing population which results in contamination of the environment. In India, crop production increased to 100 %, but the cropping area has increased marginally by 20 %. Pesticides have played a major role in achieving the maximum crop production but maximum usage and accumulation of pesticide residues is highly detrimental to aquatic and other ecosystem. Pesticide residues in drinking water have become a major challenge over the last few years. It has been monitored in public water supply resources in National capital territory, i.e., Delhi. Organochlorine pesticides (OCPs), mainly isomers of hexachlorohexane (HCH), dichloro-diphenyl-trichloroethane (DDT), endosulphan, endrin, aldrin, dieldrin, and heptachlore, were identified from potable water samples. Results suggested that continuous consumption of contaminated water can pose severe health threats to local residents of this area. Central Pollution Control Board (CPCB), Delhi, had found α and β isomers of endosulphan residues in the Yamuna river. High concentrations of γ-HCH (0.259 μg/l) and malathion (2.618 μg/l) were detected in the surface water samples collected from the river Ganga in Kanpur, Uttar Pradesh (UP). High concentration of methyl parathion, endosulfan, and DDT were observed in water samples collected from the river at Bhagalpur, Bihar. The Industrial Toxicology Research Centre (ITRC), Lucknow (UP) study also found 0.5671 ppb concentrations of endosulfan in the river at Allahabad, UP. Similar results were found in other water samples in India.

A smartphone-readable barcode assay for the detection and quantitation of pesticide residues.

In this paper, we present a smartphone-readable barcode assay for the qualitative detection of methyl parathion residues, a toxic organophosphorus pesticide that is popularly used in agriculture worldwide. The detection principle is based on the irreversible inhibition of the enzymatic activity of acetylcholinesterase (AchE) by methyl parathion; AchE catalytically hydrolyzes acetylthiocholine iodine to thiocholine that in turn dissociates dithiobis-nitrobenzoate to produce a yellow product (deprotonated thio-nitrobenzoate). The yellow intensity of the product was confirmed to be inversely dependent on the concentration of the pesticide. We have designed a barcode-formatted assay chip by using a PDMS (polydimethylsiloxane) channel plate (as the reaction reservoir), situated under a printed partial barcode, to complete the whole barcode such that it can be directly read by a barcode scanning app installed on a smartphone. The app is able to qualitatively present the result of the pesticide test; the absence or a low concentration of methyl parathion results in the barcode reading as "-", identifying the test as negative for pesticides. Upon obtaining a positive result (the app reads a "+" character), the captured image can be further analyzed to quantitate the methyl parathion concentration in the sample. Besides the portability and simplicity, this mobile-app based colorimetric barcode assay compares favorably with the standard spectrophotometric method.

A simple and sensitive fluorescent sensor for methyl parathion based on l-tyrosine methyl ester functionalized carbon dots

In this paper, a simple and sensitive fluorescent sensor for methyl parathion is developed based on l-tyrosine methyl ester functionalized carbon dots (Tyr-CDs) and tyrosinase system. The carbon dots are obtained by simple hydrothermal reaction using citric acid as carbon resource and l-tyrosine methyl ester as modification reagent. The carbon dots are characterized by transmission electron microscope, high resolution transmission electron microscopy, X-ray diffraction spectrum, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The carbon dots show strong and stable photoluminescence with a quantum yield of 3.8%. Tyrosinase can catalyze the oxidation of tyrosine methyl ester on the surface of carbon dots to corresponding quinone products, which can quench the fluorescence of carbon dots. When organophosphorus pesticides (OPs) are introduced in system, they can decrease the enzyme activity, thus decrease the fluorescence quenching rate. Methyl parathion, as a model of OPs, was detected. Experimental results show that the enzyme inhibition rate is proportional to the logarithm of the methyl parathion concentration in the range 1.0×10−10–1.0×10−4M with the detection limit (S/N=3) of 4.8×10−11M. This determination method shows a low detection limit, wide linear range, good selectivity and high reproducibility. This sensing system has been successfully used for the analysis of cabbage, milk and fruit juice samples.

Pupillary light response in guinea pigs and swine exposed to organophosphate agents (1143.5)

Here we report a study to more precisely define and quantify the relationship between organophosphate agent exposure, including pesticides and nerve agents, with cholinesterase inhibition and the ocular biomarkers that are induced. A thorough investigation of these relationships was conducted to subsequently refine pupillary algorithms for the automated detection of organophosphate exposures with greater specificity regarding level of exposure, the extent of cholinesterase inhibition, and the temporal presentation and persistence of the ocular biomarkers. A guinea pig model was exposed to varying concentrations of parathion (pesticide), soman and VX (nerve agents) to methodically detail both the temporal and quantitative occurrence of pupillary deficits (anticholinesterase biomarkers) to determine the most sensitive, accurate diagnostic algorithms in these animal models. Dose‐response curves and temporal‐response curves for both pupillary deficits and generalized symptoms were developed for each agent used. Based upon previous studies dose ranges were conducted from the LD50 to 3000‐fold below the LD50 to incorporate lethal and sub‐lethal exposures without decreasing the potential sensitivity of the ocular biomarkers. In addition, cholinesterase assays were performed at various time points post‐exposure. The key finding of this study was that after exposure to organophosphates changes in pupillary response were detected prior to changes in acetylcholine esterase levels in guinea pigs. This opens the possibility of early detection to organophosphate exposure in a non‐invasive manner that does not require the use of enzyme markers. We are in the process of duplicating these studies in swine and swine data will be presented.Grant Funding Source: Supported by Defense Threat Reduction Agency

Antigenotoxic Effect of Curcumin and Carvacrol against Parathion Induced DNA Damage in Cultured Human Peripheral Blood Lymphocytes and Its Relation to GSTM1 and GSTT1 Polymorphism

In recent years, the use of organophosphorus pesticides has been extensively increased and these compounds signify a major class of agricultural pesticides today. We studied antigenotoxic potential of curcumin and carvacrol against the parathion induced DNA damage in cultured peripheral blood lymphocytes using sister chromatid exchanges as a biomarker of genotoxicity. Heparinised fresh blood from healthy individuals was treated with 2.5 μg/mL concentration of parathion in presence of curcumin and carvacrol in order to observe the antigenotoxic potential of both curcumin and carvacrol. Significant reduction (P < 0.05) was observed in the frequencies of SCEs in presence of 10 μg/mL and 15 μg/mL concentrations of curcumin as compared to parathion exposed sample. Similarly carvacrol had significant (P < 0.05) antigenotoxic effect at the concentrations of 2.5 μg/mL and 5.0 μg/mL against the parathion. We also studied the effect of GSTT1 and GSTM1 on genotoxicity of parathion and antigenotoxic potential of curcumin and carvacrol. We did not observe any significant effect (P > 0.05) of GSTT1 and GSTM1 polymorphism on genotoxicity of parathion and antigenotoxic potential of curcumin and carvacrol.

Nonenzymatic sensing of methyl parathion based on graphene/gadolinium Prussian Blue analogue nanocomposite modified glassy carbon electrode

A new nonenzymatic electrochemical sensor was developed for sensitive detection of methyl parathion based on graphene nanosheets (GNs)/gadolinium Prussian Blue analogue (gadolinium hexacyanoferrate, GdHCF) modified glassy carbon electrode. The new sensor combined the individual properties of GNs (high conductivity and adsorption affinity) and GdHCF (high surface area and special catalytic activity), and realized efficient enrichment and electrochemical stripping voltammetric detection of methyl parathion. Under optimum conditions, the reduction current was proportional to methyl parathion concentration over the range from 0.008 to 10 μM with a detection limit of 1 nM. The sensor displayed high sensitivity, acceptable stability and selectivity, and realized reliable quantification of methyl parathion in practical environment samples.

Microwave induced degradation of parathion in the presence of supported anatase- and rutile-TiO2/AC and comparison of their catalytic activity

In this study, nano-sized anatase or rutile TiO2-supported activated carbon (A-TiO2/AC or R-TiO2/AC) was developed for the microwave (MW)-induced degradation of parathion as a model contaminant in aqueous solution. The effects of selected process parameters such as anatase or rutile TiO2 content, heat-treatment temperature and time, MW irradiation time, initial parathion concentration, catalyst dose, solution pH and MW power on the degradation were studied in details. The results showed that the anatase- and rutile-TiO2 supported on AC both significantly improved the MW/AC degradation effect and the supported A-TiO2/AC showed higher MW catalytic activity than R-TiO2/AC. Also, the supported A-TiO2 on AC can be excited leading to the production of more hydroxyl radicals (OH) than the supported R-TiO2 on AC in aqueous solution under MW irradiation. Comparatively, the supported A-TiO2/AC/MW process displayed many advantages such as high degradation rate, short irradiation time, no residual intermediates, and no secondary pollution. Therefore, the supported A-TiO2/AC/MW showed to be a promising technology for the removal of parathion in wastewater treatment applications.

Coextracted dissolved organic carbon has a suppressive effect on the acetylcholinesterase inhibition assay

The acetylcholinesterase (AChE) inhibition assay is frequently applied to detect organophosphates and carbamate pesticides in different water types, including dissolved organic carbon (DOC)-rich wastewater and surface water. The aim of the present study was to quantify the effect of coextracted DOC from different water samples on the commonly used enzyme-based AChE inhibition assay. Approximately 40% to 70% of DOC is typically recovered by solid-phase extraction, and this comprises not only organic micropollutants but also natural organic matter. The inhibition of the water extracts in the assay differed greatly from the expected mixture effects based on chemical analysis of organophosphates and carbamates. Binary mixture experiments with the known AChE inhibitor parathion and the water extracts showed reduced toxicity in comparison with predictions using the mixture models of concentration addition and independent action. In addition, the extracts and reference organic matter had a suppressive effect on a constant concentration of parathion. The present study thus indicated that concentrations of DOC as low as 2 mg carbon/L can impair the AChE inhibition assay and, consequently, that only samples with a final DOC concentration of less than 2 mgC /L are suitable for this assay. To check for potential suppression in environmental samples, standard addition experiments using an AChE-inhibiting reference compound are recommended.

Trichloroacetic acid assisted synthesis of gold nanoparticles and its application in detection and estimation of pesticide

Abstract Background Many analytical methods are available for detection of methyl parathion in water but they are not handy for on-site analysis. An attempt has been made to utilize stable GNP for methyl parathion detection by sensing the peak at 400 nm generated due to the interaction between methyl parathion and GNP. Methods GNP was produced by reduction of chloroauric acid solution by trichloroacetic acid in alkaline medium in presence of CTAB. Sensor properties of GNP were studied by varying the concentration of methyl parathion in gold sol from 0 to 500 ppm. Results and discussion GNP stabilized by CTAB showed only one peak at 532 nm and one broad peak near 300 nm was observed for pure methyl parathion. But as soon as methyl parathion was added in the GNP solution, one new peak at 400 nm developed in addition to the other two peaks. More interestingly, a quantitative decrease of the absorbance at 532 nm of GNP and increase of the absorbance at 400 nm, the new peak, were observed when methyl parathion concentration increased from 10 to 500 ppm. Conclusions The UV-VIS measurement and TEM images confirmed that the surfactant capped GNP can act as a colorimetric sensor for detection and estimation of methyl parathion pesticide present in water in ppm level.

Quantum dot immobilized acetylcholinesterase for the determination of organophosphate pesticides using graphene-chitosan nanocomposite modified electrode

We have fabricated a sensitive acetylcholinesterase biosensor that is based on dual-signal amplification. A large amount of enzyme was immobilized on a glassy carbon electrode via specific binding between functionalized ZnSe quantum dots and acetylcholinesterase, and a graphene–chitosan nanocomposite was introduced that improves the response. These two factors render the biosensor highly sensitive to acetylthiocholine chloride. Organophosphate pesticides were detected with this biosensor using methyl parathion as a model enzyme inhibitor. Under optimal conditions, there is a linear relationship between the percentage of inhibition (I%) and the log of the concentration of methyl parathion in the 0.5 nM to 0.5 μM range, with a 0.2 nM detection limit (at an S/N of 3). The biosensor displays acceptable reproducibility and relatively good storage stability. It was successfully employed to the determination of methyl parathion in spiked water and soil samples.

Electrochemical Sensor Based on the Graphene-Nafion Matrix for Sensitive Determination of Organophosphorus Pesticides

A graphene-Nafion matrix modified glassy carbon electrode (Graphene-Nafion/GCE) was developed for the determination of organophosphorus pesticides (OPs). Graphene nanosheets were synthesized chemically by the Hummers method. The electrochemical properties of the Graphene-Nafion/GCE were investigated by cyclic voltammetry and square-wave voltammetry. It was found that the graphene-Nafion matrix not only enhanced the adsorption to OPs, but also improved the sensitivity of the OPs determination due to the synergistic effect of graphene nanosheets and Nafion. Methyl parathion was selected as a model of OPs. Compared to the unmodified electrode, the peak current obviously increased and the reduction peak potential positively shifted. Under the optimum conditions, the response current of stripping voltammetry was linearly related to the concentration of methyl parathion over the range from 0.02 to 20 µg/ml with a detection limit of 1.6 ng/ml. The sensor was successfully applied in the determination of methyl parathion in vegetable samples by the standard addition method.