Determination Of Imidacloprid Research Articles

Tokat ili su örneklerinde insektisit imidacloprid kalıntılarının enzim-bağımlı immunosorbent analizi (ELİSA) ile belirlenmesi

Imidacloprid is a common neonicotinoid insecticide applied in agricultural fields worlwide. Imidacloprid residues can be detected in water resources as it can accumulate in the surface and ground water after insecticide applications through many years. Because of this, a fast and efficient method, enzyme-linked immunosorbant assay (ELISA), is used to determine the imidacloprid levels in water sample collected from Tokat city water system and compared with a commercially avaliable bottled water sample. Imidacloprid residue was not detected in bottled water sample. However, imidalcoprid residues was detected in Tokay city water close to the maximum residue limit of imidacloprid. The results indicate that the Tokat city water system could be at the risk of imidacloprid contamination. This study also shows that ELISA technique can be effectively used for imidacloprid determination since it is fast and reliable and well correlated with other time consuming and cost-effective analytical methods.

Determination of imidacloprid and its relevant metabolites in tomato using modified QuEChERS combined with ultrahigh-pressure liquid chromatography/Orbitrap tandem mass spectrometry.

Red tomato processing is one of the leading industries in Xinjiang, but also the largest export industry. In the process of tomato planting, imidacloprid (IMI) is often used to kill aphids, which poses the risk of pesticide residue. However, as daily consumables, pesticide residue on tomatoes may cause a potential threat to human health. Therefore the aims of this research were to study the residue dynamics of IMI pesticides in tomatoes by monitoring field experiments and to investigate the fate of IMI and its metabolites under Xinjiang field conditions. In the field trials, three different doses of IMI were sprayed on tomato during the fruit setting stage. Degradation of IMI and residue behaviors of its metabolites at different stages were systemically traced and evaluated by ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC/Q-Orbitrap MS). An accurate mass tool was used as the main method to identify the IMI metabolites. The improved method showed high efficiency in detecting IMI and 6-chlorinated nicotinic acid (6-CNA), being able to determine hazardous pesticides at trace levels. The fate of IMI in field tomato was investigated over 28 days. The metabolic mechanism of IMI in tomato is: OH products in the early stage and carbonyl products in the late stage. Under natural conditions, pesticides in tomatoes will gradually decrease with time. In this process, olefin IMI is produced, but it is almost completely metabolized after 28 days. Therefore even 10 times the recommended dose of IMI pesticide will not endanger human health. © 2019 Society of Chemical Industry.

Fabrication of a highly sensitive and selective modified electrode for imidacloprid determination based on designed nanocomposite graphene quantum dots/ionic liquid/multiwall carbon nanotubes/polyaniline

In this paper, a simple, selective and sensitive electrochemical method was developed for the determination of imidacloprid. To fabricate the modified electrode, at first, a glassy carbon electrode (GCE) was modified with a nanocomposite consist of graphene quantum dots/ionic liquid/multiwall carbon nanotubes (GQDs/IL/MWCNTs). Then, polyaniline (PANI) film was formed on the surface of GQDs/IL/MWCNTs by electropolymerization via cyclic voltammetry at a surface of the modified GCE. Field emission scanning electron microscopy and transmission electron microscopy were used for elucidation the GQDs/IL/MWCNTs/PANI surface characterization. For investigation the electrochemical behavior of imidacloprid at the GCE/GQDs/IL/MWCNTs/PANI, cyclic voltammetry and differential pulse voltammetry techniques were utilized. Also, the effective variables on the modified electrode such as pH, electropolymerization cycles, accumulation potential and accumulation time were studied. The proposed modified electrode showed a linear range from 0.03 to 12.0 μmol L−1 imidacloprid with a detection limit of 9 nmol L−1. This modified electrode exhibited good repeatability and excellent selectivity. The proposed modified electrode was employed for imidacloprid determination in vegetable samples.

Synthesis of core-shell magnetic molecularly imprinted polymer for the selective determination of imidacloprid in apple samples.

This work demonstrates the synthesis and characterization of core-shell magnetic molecularly imprinted polymers based on surface imprinting using methacryloyl chloride as a functional monomer for the selective extraction of imidacloprid (template) from apple fruit. The characterization analysis results ensured the successful synthesis of the magnetic molecularly imprinted polymers owing to their heterogeneous structure and good magnetic properties. An isothermal binding test was assessed with a pseudo-second-order kinetic model, and the kinetic results fit well to the Freundlich isothermal model. The polymers exhibited an adsorption capacity of 5.75mg/g for the target analyte with a good selective extraction ability. In addition, the polymers can be reused several times without significant performance loss. The molecularly imprinted polymers showed good performance in the analysis of spiked apple sample with a linear range of 0.05-1.0mg/L, a limit of detection of 0.048mg/L and a limit of quantification of 0.146mg/L (S/N=3/10). The recoveries of the samples were 77.66-96.57% and their respective relative standard deviations were 3.36-0.45%. All the results indicated that the proposed method provided good selective extraction, as qualifying the analytical standards.

A sensitive electrochemical sensor based on polypyrrole/electrochemically reduced graphene oxide for the determination of imidacloprid

The glassy carbon electrode (GCE) was modified by electrochemically reduced graphene oxide (ERGO) and polypyrrole (PPy) prepared by simple cyclic voltammetry (CV) electropoly­merization. The PPy/ERGO modified electrode (PPy/ERGO/GCE) was used as a platform of electrochemical sensor to detect imidacloprid (IMI) insecticide. CV and differential pulse voltammetry (DPV) were chosen as the methods to investigate of the electrochemical behavior of IMI on PPy/ERGO/GCE surface. Scanning electron microscopy (SEM) and Raman spectra were utilized to describe the morphology and structure of the modified electrode. Experimental parameters were optimized, such as the number of polymerization cycles, scan rate and the pH value of electrolyte. Under the optimized conditions, when the concentration of IMI was in the range of 1-10 μM and 10-60 μM, the increase of reduction peak current was linear with the concentration of IMI, and the low detection limit was found to be 0.18 μM (S/N = 3). Results showed that PPy/ERGO/GCE demonstrated satisfactory reproducibility and stability, and has great potential in actual sample testing.

Modified Screen-Printed Electrode for Determination of Imidacloprid in Water Samples: A Preliminary Study

A preliminary assessment of a simple and rapid electrochemical method was carried out to analyse imidacloprid (IMI) in water samples using cyclic voltammetry (CV) based on modified screen-printed gold electrode (SPGE). Self-assembled monolayer (SAM) was optimized using 11-mercaptoundecanoic acid (11-MUA) with several parameters such as scan rates, type of supporting electrolyte, and pH of the supporting electrolyte. The modified SPGE showed high suppressed current against the potential due to the formation of a monolayer on the electrode surface. Surface morphology of the electrode was analysed using Scanning Electron Microscopy (SEM) confirming that 11-MUA was present on the modified SPGE. The water samples were collected from GM Peladang, Kuala Terengganu and two locations at Universiti Malaysia Terengganu. Method detection limit was expressed as limit of detection (LOD) and limit of quantification (LOQ) for modified SPGE which were calculated at 3.784 and 12.613 mg/L in water samples, respectively. This study showed that the reduction peak current observed on the modified electrode was lower compared with oxidation peak current. Hence, gold is unsuitable for IMI detection.

Effects of Spent Mushroom Compost on Degradation of Imidacloprid in Soil and Plant

The changes of imidacloprid content in contaminated soil and tomato plants were studied when the Spent mushroom compost(SMC) was added as environmental remediation material. Tomato planting experiment was carried out by applying SMC and chicken dung to soil containing imidacloprid at a ratio of 1:1, 0:1 and 1:0. A HPLC method was developed for the determination of imidacloprid in soil and tomato plants. The result is that the degradation rate of imidacloprid in the soil of SMC as substrate is faster, and its half-life is 11.2 days. The SMC have certain adsorption effect to imidacloprid, makes the imidacloprid content in tomato plants grown on the basis of SMC is lower. Thus the SMC can effectively promote the process of adsorption and degradation of imidacloprid in the soil.

Simultaneous magnetic solid phase extraction of acidic and basic pesticides using triazine-based polymeric network modified magnetic nanoparticles/graphene oxide nanocomposite in water and food samples

In this work, a triazine-based polymeric network modified magnetic nanoparticles/graphene oxide (TPN/Fe3O4 NPs/GO) nanocomposite was successfully synthesized and used as an effective nanosorbent in simultaneous magnetic solid phase extraction of basic and acidic pesticides from food and water samples by HPLC-UV. Imidacloprid (IMI) and 2,4-dichlorophenoxyacetic acid (2,4-D) were selected as model basic and acidic pesticides, respectively. The synthesized TPN/Fe3O4/GO was characterized by field emission-scanning electron microscopy (FE-SEM), Fourier transform-infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM) and thermogravimetric analysis (TGA). Some parameters that affect the extraction efficiency such as pH of solution, sorbent amount, salt amount, extraction time, desorption solvent volume and desorption time were optimized by central composite design. However, type of desorption solvent and sample volume were optimized by one variable at a time method. Under optimum conditions, the calibration curve was linear in the range of 0.5–500 μg L−1 and 5.0–500 μg L−1 for IMI and 2,4-D, respectively. The limits of detection (LODs) for IMI and 2,4-D were 0.17 and 1.7 μg L−1, respectively. Also, the limits of quantification (LOQs) for IMI and 2,4-D were 0.5 and 5.0 μg L−1, respectively. The relative standard deviations (RSDs) were <8.6% (n = 6). The proposed method was successfully applied for extraction and determination of IMI and 2,4-D in cucumber, tomato and water samples and satisfactory results (recoveries ≥90%) were obtained.

Simultaneous Determination of Imidacloprid and Its Metabolites in Cotton and Soil

An easy, simple and efficient analytical method for the estimation of residues of imidacloprid and its metabolites like 6-chloronicotinic acid (6-CNA), nitroguanidine, olefin, nitrosamine, urea and 5-hydroxy, in different fractions of cotton comprising cotton leaves, lint, oil, seed cake and soil is reported. Sample preparation consisted of extraction of residues from matrices using acetonitrile followed by clean up by dispersive solid phase tube. The residues were estimated using high performance liquid chromatograph (HPLC) equipped with PDA detector system, C18 column and confirmed by Liquid Chromatograph Tandem Mass Spectrometry (LC-MS/MS). HPLC grade acetonitrile: water (30: 70) was used as mobile phase @ 0.3 mL min−1. The recoveries of imidacloprid and its metabolites spiked at 0.01, 0.05 and 0.1μg g−1 levels were in the range of 80 to 94 per cent. The limit of quantification (LOQ) of the method was worked out to be 0.01 mg kg−1. The analytical method was validated in terms of parameters including selectivity, linearity, repeatability, reproducibility and accuracy.

Polyelectrolyte nanocapsule probe for the determination of imidacloprid in agricultural food samples

ABSTRACTLayer-by-layer (LBL) technique is a well-established method for the formation of nanocapsules, which could encapsulate nanoparticles by polyelectrolyte and has received great interest in some areas of research. In this study, colloidal gold nanoparticles (AuNPs) were used as a vehicle for loading horseradish peroxidase (HRP), and AuNPs-HRP was encapsulated by using LBL technique to form a signal amplification nanocapsule probe. Based on the probe, an immunoassay was developed for the detection of imidacloprid in agricultural food samples (rice, pear and cabbage). The IC50 value of the assay was 0.11 ng mL−1 which was 8-9954 times lower than those of traditional ELISAs and well below the maximum residue limits (MRLs) permitted by the European Union (EU). The recoveries of imidacloprid from three different samples were 80.34–120.84% that had a good correlation (R2 = 0.9739) with those obtained by the commercial kit. The developed assay could provide a sensitive method for detection of imidacloprid.

Determination of imidacloprid in beehive samples by UHPLC-MS/MS

Imidacloprid is a systemic insecticide belonging to the neonicotinoid family. It was the first neonicotinoid introduced in the mid-1990s, and since then, its use has grown rapidly to control pests in a variety of agricultural crops. Several studies have shown that neonicotinoids translocate to the nectar and pollen of treated plants, which represents a potential risk to pollinators. Therefore, an open-field feeding study was carried out. For this purpose, 30 beehives of Apis mellifera L. were installed in the same apiary. All colonies were in similar health and population conditions when assays were started. For seven weeks, colonies were fed with sucrose syrup with different concentrations of imidacloprid: 15, 30, 120 and 240 μg kg−1. Thus, the assays were divided into four treatments and a witness (Control) with no added imidacloprid. To check the hives' exposure to imidacloprid and evaluate its distribution, sampling of adult worker bees and larvae was performed before, during and after the whole feeding period (7 weeks). Furthermore, in the 15th week, honey and beeswax (honeycomb) samples were collected from the brood chamber and honey super of all hives. Analytical methodologies for sample preparation based on the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) procedure were optimized and validated. After soaking the bees and honey samples and the extraction using acetonitrile with MgSO4 and NaCl salts, a dispersive solid-phase extraction (d-SPE) step with MgSO4, PSA and C18 was applied. Melted beeswax was subjected to an acetonitrile extraction, followed by freeze-out and d-SPE with PSA and C18. Extracts were evaluated in a UHPLC-MS/MS system. LOQ (μg kg−1) values were 0.25, 0.50 and 1 for honey, bees and beeswax, respectively. Satisfactory recovery performance was achieved with relative standard deviation ≤20%. Residue concentrations of imidacloprid in samples showed correlation with the doses supplied, indicating exposure of the beehives to the insecticide. Honey stored approximately 60% of the loaded imidacloprid through syrup feeding.

An Electrochemical Sensor Based on Electropolymerization of ß‐Cyclodextrin and Reduced Graphene Oxide on a Glassy Carbon Electrode for Determination of Neonicotinoids

AbstractAn electrochemical sensor of glassy carbon electrode modified with reduced graphene oxide and β‐cyclodextrin (GCE/rGO/β‐CD) was developed as an effective alternative in the determination of neonicotinoid insecticides, imidacloprid, clothianidin and thiamethoxam, in honey samples. The peak current variation obtained with the proposed sensor was higher compared to the bare GCE in all the analytes. In the determination of imidacloprid the response increased by 1300 %, clothianidin by 670 % and thiametoxam by 630 %. In addition, the optimization of the experimental conditions provided the construction of a sensor with greater sensitivity. The study of interferers showed that inorganic ions (Ca2+, Mg2+, Fe2+, K+, Na+, e NH4+) and other insecticides (acetamiprid and dinotefuran) did not influence the reduction of imidacloprid, clothianidin and thiamethoxam. The determination of imidacloprid, clothianidin and thiamethoxam in honey samples exhibited recovery values within the EPA range (between 107.75 and 116 %). In conclusion, the developed sensor GCE/rGO/β‐CD proved to be an effective alternative in the determination of neonicotinoid insecticides in honey samples.

Optimization of an Electrochemical Sensor for Determination of Imidacloprid Based on β‐cyclodextrin Electropolymerization on Glassy Carbon Electrode

AbstractAn electrochemical sensor based on electropolymerization of β‐cyclodextrin (β‐CD) on a glassy carbon electrode (GCE) was developed for the determination of imidacloprid (IMP). That insecticide is the most commonly used insecticides globally and has been related to the death of bee colonies around the world are imperative. So the development of a simple, cheap and sensitive method for IMP determination is essential. This work aims the modification of a GCE by β‐CD film. The analytical response obtained with GCCE/β‐CD in the presence of the IMP showed an increase in the peak current variation of 947 % in relation to the bare GCE, indicating that the analyte was encapsulated in the β‐CD increasing the detection sensitivity. The followed experimental conditions were optimized: potential range (−1.3 to 0.9 V), presence or absence of dissolved oxygen (presence) and stirring during the electropolymerization (with agitation), number of cycles (5 scans), electrolyte pH (pH=5.0), scan rate (100 mV s−1) and concentration of β‐CD (6 mol L−1). The optimization promoted a peak current variation increase of 57 %, developing a more sensitivity methodology.

Designing of fluorescent and magnetic imprinted polymer for rapid, selective and sensitive detection of imidacloprid via activators regenerated by the electron transfer-atom transfer radical polymerization (ARGET-ATRP) technique

In this work, we report on a dual-behavior electrochemical/optical sensor for sensitive determination of Imidacloprid by fluorescent dye (fluorescein, FL) and imprinted polymer modified europium doped superparamagnetic iron oxide nanoparticles (FL@SPIONs@MIP). The imidacloprid (IMD)-imprinted polymer was directly synthesized on the Eu-SPIONs surface via Activators regenerated by the electron transfer-atom transfer radical polymerization (ARGET-ATRP) technique. Preparation, characterization and application of the prepared FL@SPIONs@MIP were systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), fluorescence spectroscopy and electrochemical techniques. The electrochemical experiments exhibited a remarkable selectivity of the prepared sensor towards IMD. Determination of IMD by the square wave stripping voltammetry method represented a wide linear range of 0.059–0.791 μg L−1 with a detection limit of 0.0125 μg L−1. In addition, the fluorescence method shows a linear range of 0.039–0.942 μg L−1 and LOD of 0.0108 μg L−1. The fluorescence property of prepared FL@SPIONs@MIP was used for rapid, on-spot but selective detection of IMD in real samples. The proposed electrode displayed excellent repeatability and long-term stability and was successfully applied for quantitative and trace level determination of IMD in several real samples.

Electroanalysis of Imidacloprid Insecticide in River Waters Using Functionalized Multi-Walled Carbon Nanotubes Modified Glassy Carbon Electrode

In this work, a functionalized multi-walled carbon nanotubes modified glassy carbon electrode (GCE/MWCNT-f) was optimized for the direct determination of imidacloprid (IMC) insecticide in river water. The functionalized material was characterized by infrared spectroscopy with Fourier transform (FTIR) and the modified electrode by scanning electron microscopy (SEM) and cyclic voltammetry (CV). Results revealed that the GCE/MWCNT-f effectively increased the response toward IMC reduction by enhancing the reduction peak current and decreasing the peak potential in comparison with the bare electrode. After optimizing the electroanalytical conditions, the GCE/MWCNT-f showed a linear voltammetric response at concentration ranging from 2.40 × 10−7 to 3.50 × 10−6 mol L−1, with detection and quantification limits of 4.15 × 10−7 mol L−1 and 1.38 × 10−6 mol L−1, respectively. The recovery rate of IMC in spiked river water samples varied from 90–95%. Thus, this sensor can be a promising tool for the analysis and monitoring of IMC in complex environmental matrices.

Molecularly imprinted polymer on graphene surface for selective and sensitive electrochemical sensing imidacloprid

A novel and simple imprinting route based on graphene (GN) was proposed to fabricate an electrochemical sensor for sensitive and selective determination of imidacloprid (IDP) residue. In this route, p-vinylbenzoic acid (VBA) was utilized as functional monomer to immobilize onto GN in N,N-dimethylformamide (DMF) solvent via π-π interaction, directing the polymerization of uniform molecularly imprinted polymers (MIP) layers on the surface of GN sheets. Besides, quantitative control of the synthesis of MIP/GN and the preparation of MIP/GN modified glassy carbon electrode (GCE) were carried out, which were rarely found in other papers. Thus, the proposed sensor possesses highly improved stability and specific recognition ability. The adsorption isotherm study indicated that the MIP layer on GN surface is monolayer and the structure is homogeneous. The peak current of IDP on MIP/GN modified GCE is linear with IDP concentration in the range of 0.5–15μM with a detection limit of 0.10μM. In addition, the novel method was further applied to detect IDP in brown rice samples with satisfactory results.

Facile fabrication and characterization of silver nanodendrimers supported by graphene nanosheets: A sensor for sensitive electrochemical determination of Imidacloprid

In this work, we report a novel electrochemical sensor for sensitive determination of Imidacloprid by facile electrodeposition of Ag nanodendrimers (AgNDs) on the graphene nanosheets (GNs) modified glassy carbon electrode (GCE). The AgNDs were directly electrodeposited on the electrode surface via potentiostatic method without using any templates, surfactants or stabilizers. Preparation, characterization and application of this sensor were systematically investigated. The relationship between AgNDs morphological evolution and electrodeposition conditions (applied potentials and times) was investigated. The morphology and constituent of the AgNDs/GNs/GCE surface was characterized using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS) techniques. The electrochemical experiments exhibited remarkable catalytic activity of AgNDs/GNs/GCE toward Imidacloprid reduction. The tree-like hierarchical structure of nanodendrimers is an appropriate structure for design of effective electrocatalysts. Moreover, the synergistic effect between GNs and AgNDs significantly improves the electrochemical responses. Determination of Imidacloprid by differential pulse voltammetry (DPV) method represented a wide linear range of 1.0×10−6 to 1.0×10−4M with detection limit of 8.14×10−7M. The proposed electrode displayed excellent repeatability and long-term stability; furthermore, the practicability of this sensor was successfully demonstrated by determination of Imidacloprid in several real samples.

Persistence and Degradation of Imidacloprid in Wheat Crop

Present study was conducted to investigate the levels and persistence of imidacloprid residues in wheat grains and straw of field crop samples grown from treated seed and foliar application. Objective of the study was to assess the best practices that may be used to produce safe grains and straw. Residual uptake of imidacloprid was measured after seed treatments at four dosage levels of seed. Each sample of 25g treated seed was sown in a separate 5ft2 plot.The absorption of imidacloprid residues was investigated by spraying the crops with 1ml and 5ml of 6 mgmL-1 solution of 200SL Confidor (imidacloprid). The results helped in determining the maximum allowable limits of imidacloprid application (foliar or seed treatment) on wheat, which would prevent the residues from exceeding the MRL. The quantitative determination of imidacloprid suggested that the lowest seed treatment level (i.e. 0.015g/25g seed) may be used to produce a residues-free crop.

Preparation of hydrophilic surface-imprinted ionic liquid polymer on multi-walled carbon nanotubes for the sensitive electrochemical determination of imidacloprid

A hydrophilic ionic liquid monomer was immobilized on carboxylated MWNTs by ion exchange, then reversible addition–fragmentation chain transfer precipitation polymerization was performed in the presence of a template, imidacloprid.

Preconcentration of imidacloprid with β - cyclodextrin polymer and analysis by HPLC

Cyclodextrins are type of oligosaccharide consisting of glucose units. Cyclodextrins are of mainly of three types α, β and γ consisting of six, seven and eight glucose units respectively joined with α-1,4-glycosodic linkage. β-cyclodextrin is a very stable, most useful and low priced oligosaccharide. Guest molecules can be incorporated in its cavity to form supramolecular complex. β-cyclodextrin is modified with cross-linker 1,4-butanedioldiglycidyl ether to form polymer. This sorbent was used as a support for the solid phase extraction of imidacloprid from water samples and these samples were analysed with the help of HPLC. For quantitatative extraction(≥95%) of imidacloprid with β - cyclodextrin polymer various parameters like pH, amount of sorbent, sample volume, contact time and volume of eluent were optimized. The HPLC analysis of imidacloprid was done at λ max at 278nm using 80:20 acetonitrile: water as a mobile phase with a flow rate 1.0ml/min. R t for imidacloprid comes at 2.9 min. Enrichment factor is 75. LOD is 0.45 ng/ml and LOQ is 1.5 ng/ml. Relative standard deviation is 2.1%. The developed method was applied successfully for the determination of Imidacloprid in various water samples.