Determination Of Carbaryl Research Articles

Preparation, optimization and application of poly(ethylene glycol)methyl ether methacrylate/urethane methacrylate as a new polar phase for stir bar sorptive extraction

The aim of this paper is to discuss the determination of carbaryl in a water sample using a stir bar sorptive extraction method based on a new polar extraction phase coupled with HPLC-DAD.

Bienzyme self-assembled monolayer on gold electrode: An amperometric biosensor for carbaryl determination

A new electrochemical biosensor based on the covalent immobilization of two enzymes on self-assembled monolayer attached to a polycrystalline gold electrode is proposed, experimentally. The acetylcholinesterase (AChE) and cholineoxidase (ChO) are two enzymes that covalently co-immobilized on the mercaptopropionic acid self-assembled monolayer on polycrystalline gold electrode (Au-MPA-AChE/ChO SAM). Fabrication steps and electrochemical interaction of the Au-MPA-AChE/ChO SAM with carbaryl were monitored by general electrochemical methods like cyclic voltammetry (CV) and chronoamperometry (CA), and by a more advanced method, electrochemical impedance spectroscopy (EIS) in the presence of parabenzoquinone (PBQ) or K3[Fe(CN)6] redox probes. The close distances between two immobilized enzymes on Au-MPA SAM result in preconcentration of choline, the product of acetylcholine hydrolysis by AChE, in ChO nano-environment. Enzyme activity was measured by chronoamperometric tracing of hydroquinone from the reduction of PBQ mediator which in turn is oxidized at Au electrode in diffusion layer. Carbaryl was chosen as a model toxin and its inhibition characteristics were utilized for the toxin detection. The linear range for the determination of Carbaryl was 10–1000 nmol l−1. A limit of detection 5.96 nmol l−1 was obtained.

P-Amino benzenesulfonic acid functionalized gold nanoparticles: Synthesis, colorimetric detection of carbaryl and mechanism study by zeta potential assays

Combining the intriguing optical properties with the inherent zeta potential induced instability properties of p-amino benzenesulfonic acid functionalized gold nanoparticles (PABSA-Au NPs), a novel colorimetric detection method for carbaryl was developed. Both the color and zeta-potential of the sensor changed obviously when carbaryl was added, the limit of detection (LOD) was determined to be 0.25μM (0.05025mg/L), which is in accord with the maximum contamination level of 0.05mg/L for carbaryl as defined by the Chinese Environmental Protection Agency. Furthermore, the detection system presents excellent anti-disturbance ability when exposed to a series of interfering ionic/pesticides mixtures and can be applied to the determination of carbaryl in real different water samples such as the Yangtze River sample and East Lake water samples with the LOD as low as 0.25μM and 0.10μM, respectively. It is noteworthy that the surface zeta potential measurements are used as a new tool to investigate the aggregation mechanism of the nanoprobes. In addition, our detection system can realize relatively effective removal of carbaryl.

Selective microextraction of carbaryl and naproxen using organic–inorganic monolithic columns containing a double molecular imprint

We report on an organic–inorganic hybrid material that was double imprinted with the insecticide carbaryl and the anti-inflammatory drug naproxen by a single-step method and that can serve for selective microextraction of the two analytes. The materials, in the form of monolithic columns, were characterized by scanning electron microscopy and Fourier transform IR spectra. A simple, rapid and sensitive method was then developed for the simultaneous determination of carbaryl and naproxen in lettuce and river water using these columns for microextraction, HPLC for separation, and a diode array for UV detection. The limits of detection (at S/N = 3) and quantification (at S/N = 10) are in the ranges of 2.5 – 8.8 μg kg−1 and 2.3 – 8.0 μg L−1 for lettuce and Yangtze River water, respectively. The recoveries of this method range from 93.0 to 108 % (in case of analyzing lettuce and river water), and relative standard deviations are <8.9 %.

Acetylcholinesterase Biosensor Based on Poly (diallyldimethylammonium chloride)-multi-walled Carbon Nanotubes-graphene Hybrid Film

Abstract In this paper, an amperometric acetylcholinesterase (AChE) biosensor for quantitative determination of carbaryl was developed. Firstly, the poly (diallyldimethy-lammonium chloride) -multi-walled carbon nanotubes-graphene hybrid film was modified onto the glassy carbon electrode (GCE) surface, then AChE was immobilized onto the modified GCE to fabricate the AChE biosensor. The morphologies and electrochemistry properties of the prepared AChE biosensor were investigated by using scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. All variables involved in the preparation process and analytical performance of the biosensor were optimized. Based on the inhibition of pesticides on the AChE activity, using carbaryl as model compounds, the biosensor exhibited low detection limit, good reproducibility and high stability in a wide range. Moreover, the biosensor can also be used for direct analysis of practical samples, which would provide a new promising tool for pesticide residues analysis.

Enhancement of sensitivity for the spectrophotometric determination of carbaryl using dispersive liquid microextraction combined with dispersive μ-solid phase extraction

This work reports a sensitive spectrophotometric method for the determination of carbaryl (CBR). The method is based on the extraction of CBR using a two-step microextraction method, dispersive liquid microextraction (DLME) combined with dispersive micro-solid phase extraction (D-μ-SPE) before its detection by spectrophotometry. 1-Octanol was used as the extractant in DLME. For the D-μ-SPE method, magnetic nanoparticles (Fe3O4) functionalized with 3-aminopropyl-triethoxysilane (APTS) were used as the adsorbent to interact with the 1-octanol in DLME. The extracted CBR was spectrophotometrically detected at 480 nm after its derivatization with 2-naphthylamine-1-sulfonic acid (ANSA). The factors affecting the extraction were investigated in detail. The optimal conditions for the DLME were 150 μL of 1-octanol and vortex speed of 3200 rpm for 2 min. For the D-μ-SPE, APTS magnetic nanoparticles (10 mg) was used as the adsorbent, acetonitrile was used as the desorption solvent and the optimum time for desorption was 4 min sonication. The enrichment factor obtained was 2730. The linear range was 10–100 ng mL−1, the limit of detection was 8 ng mL−1, while the limit of quantitation was 26 ng mL−1 and the relative standard deviation was 8.5% from five replicates. The recovery of CBR from three spiked concentration levels of 25, 50 and 75 ng mL−1 was 97.3–108.1%. The method was successfully applied for the determination of CBR in tap water, field water and fruit juice samples. The proposed method has high potential to be used as an efficient preconcentration method for CBR. The APTS magnetic nanoparticles can be reused 10 times with high extraction efficiency.

Preconcentration and determination of carbaryl and carbofuran in water samples using ionic liquids and in situ solvent formation microextraction

In the present work, a novel microextraction method named in situ solvent formation microextraction (ISFME) using ionic liquids (ILs) for preconcentration of carbaryl and carbofuran in water samples is introduced. In this method, a small amount of sodium hexafluorophosphate (NaPF6), as an ion pairing agent, was added to a sample solution containing a small quantity of 1-hexyl-3-methylimidazolium tetrafluoroborate [Hmim][BF4] as a hydrophobic ionic liquid. A cloudy solution formed as a result of formation of fine droplets of 1-hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF6]. After centrifugation, the fine droplets of the extractant phase settled to the bottom of the conical-bottom glass centrifuge tube. Analysis was carried out using HPLC-UV. To obtain the best extraction results, some experimental parameters affecting the extraction efficiency were optimized. Under optimum conditions, the calibration curve was linear in the concentration range of 0.05–50 ng mL−1 for two pesticides, with the square correlation coefficients (r2) equal to 0.998 for carbaryl and 0.997 for carbofuran. Good enrichment factors of 85 and 100 were achieved for carbaryl and carbofuran, respectively. The limits of detection (LODs) (S/N = 3) were 0.09 ng mL−1 and 0.1 ng mL−1 for carbaryl and carbofuran, respectively. The method was successfully applied to analysis of pesticide residues in water samples.

A MICELLAR LIQUID CHROMATOGRAPHIC METHOD FOR THE DETERMINATION OF CARBARYL AND 1-NAPHTHOL IN BIOLOGICAL SAMPLES

Micellar liquid chromatography (MLC) is a useful technique for the determination of compounds in biological samples. Here, a sensitive procedure has been developed for the determination of carbaryl, a phenyl-N-methylcarbamate, and its main metabolite, 1-naphthol, using a C18 column (150 mm × 4.6 mm) and fluorescence detection. After performing optimization studies with an interpretative strategy, the selected mobile phase was sodium dodecyl sulfate (SDS) 0.15 M – 6% (v/v) pentanol - NaH2PO4 0.01 M buffered at pH 3. The validation studies include linearity (r2 > 0.9999), limits of detection and quantification, (0.0325 and 0.1 µM for carbaryl; 0.125 and 0.350 µM for 1-naphthol, respectively), intra- and inter-day precisions below 4%, and robustness parameters below 5%, all of which are adequate for the quantification of these two compounds in urine and serum samples to be directly injected into the chromatographic system.

Micellar Liquid Chromatographic Determination of Carbaryl and 1-Naphthol in Water, Soil, and Vegetables

A liquid chromatographic procedure has been developed for the determination of carbaryl, a phenyl-N-methylcarbamate, and its main metabolite 1-naphthol, using a C18 column (250 mm × 4.6 mm) with a micellar mobile phase and fluorescence detection at maximum excitation/emission wavelengths of 225/333 nm, respectively. In the optimization step, surfactants sodium dodecyl sulphate (SDS), Brij-35 and N-cetylpyridinium chloride monohydrate, and organic solvents propanol, butanol, and pentanol were considered. The selected mobile phase was 0.15 M SDS-6% (v/v)-pentanol-0.01 M NaH2PO4 buffered at pH 3. Validation studies, according to the ICH Tripartite Guideline, included linearity (r > 0.999), limit of detection (5 and 18 ng mL−1, for carbaryl and 1-naphthol, resp.), and limit of quantification (15 and 50 ng mL−1, for carbaryl and 1-naphthol, resp.), with intra- and interday precisions below 1%, and robustness parameters below 3%. The results show that the procedure was adequate for the routine analysis of these two compounds in water, soil, and vegetables samples.

Four-way kinetic-excitation-emission fluorescence data processed by multi-way algorithms. Determination of carbaryl and 1-naphthol in water samples in the presence of fluorescent interferents

Four-way data were obtained by recording the kinetic evolution of excitation-emission fluorescence matrices for samples containing the analytes carbaryl and 1-naphthol, two widely employed pesticides, in the concentration ranges 0–363 μg L −1 and 0–512 μg L −1, respectively. The reaction followed was the alkaline hydrolysis of carbaryl to produce 1-naphthol, a fact which introduced strong linear dependencies and multi-linearity losses in the analyzed system. Data processing was performed with unfolded partial least-squares combined with residual trilinearization (U-PLS/RTL) and also with a suitably initialized and restricted parallel factor model (PARAFAC), combined with calibration based on multi-linear regression. U-PLS/RTL is shown to be significantly simpler in its implementation and to provide similar figures of merit. The applied chemometric strategy is able to successfully determine the analytes in water samples containing uncalibrated interferences, such as other commonly employed agrochemicals and also a naturally occurring background signal.

Development of enzyme linked immunoassay for the simultaneous detection of carbaryl and metolcarb in different agricultural products

A direct competitive enzyme linked immunosorbent assay in multi-enzyme tracers format for the simultaneous analysis of carbaryl and metolcarb in agricultural products is described in this study. The concentrations of coating antibodies and enzyme tracer were studied. Under the optimum conditions, the limits of detection of carbaryl and metolcarb were 0.15 μg L −1 and 1.2 μg L −1, respectively. Determination of carbaryl and metolcarb in fruit juices and vegetables was accomplished by simple, rapid and efficient extraction methods. Recoveries of spiked samples were great than 70%. Validation of the immunosorbent assay was conducted by comparison of results from high performance liquid chromatography (HPLC). The correlations between the data obtained using multi-enzyme tracers enzyme linked immunosorbent assay and high performance liquid chromatography were good. Results indicated that the new strategy for developing immunoassay for simultaneous quantitative determination of carbaryl and metolcarb residues was suitable in this study.

Development of a sensitivity-improved immunoassay for the determination of carbaryl in food samples

With the aim of developing a highly sensitive immunoassay for carbaryl, a hapten which had high similarity to carbaryl was synthesised using a safer and more practical approach. After it was conjugated to horseradish peroxidase, direct competitive heterologous enzyme-linked immunosorbent assay (CD-ELISA) was optimised and characterised. The assay performance conditions were investigated in details. Enhanced chemiluminescence ELISA (ECL-ELISA) was also used in preliminary studies. The assay obtained an IC(50) value (the concentration causing 50% inhibition) of 2 microg kg(-1), which was 12-fold more sensitive than previous results of homologous CD-ELISA. In ECL-ELISA, the IC(50) was further decreased 10-fold to 0.2 microg kg(-1). The CD-ELISA developed was applicable for broad conditions, and could be applied on various food samples with a more convenient pre-treatment. Average recoveries were in a range of 88.3-101.7%. The results correlated well with those obtained using high-performance liquid chromatography (HPLC) analysis (R(2) = 0.989). The ELISA developed was a great improvement in the determination of carbaryl, showing that the immunoassay developed was a simple, rapid and efficient method that was reliable for the detection of carbaryl and suitable for rapid quantitative or qualitative determination in food samples.

A greener and highly sensitive flow-based procedure for carbaryl determination exploiting long pathlength spectrophotometry and photochemical waste degradation

An environmentally friendly analytical procedure with high sensitivity for determination of carbaryl pesticide in natural waters was developed. The flow system was designed with solenoid micro-pumps in order to improve mixing conditions and minimize reagent consumption as well as waste generation. A long pathlength (100 cm) flow cell based on a liquid core waveguide (LCW) was employed to increase the sensitivity in detection of the indophenol formed from the reaction between carbaryl and p-aminophenol (PAP). A clean-up step based on cloud-point extraction was explored to remove the interfering organic matter, avoiding the use of toxic organic solvents. A linear response was observed within the range 5-200 microg L(-1) and the detection limit, coefficient of variation and sampling rate were estimated as 1.7 microg L(-1) (99.7% confidence level), 0.7% (n=20) and 55 determinations per hour, respectively. The reagents consumption was 1.9 microg of PAP and 5.7 microg of potassium metaperiodate, with volume of 2.6 mL of effluent per determination. The proposed procedure was selective for the determination of carbaryl, without interference from other carbamate pesticides. Recoveries within 84% and 104% were estimated for carbaryl spiked to water samples and the results obtained were also in agreement with those found by a batch spectrophotometric procedure at the 95% confidence level. The waste of the analytical procedure was treated with potassium persulphate and ultraviolet irradiation, yielding a colorless residue and a decrease of 94% of total organic carbon. In addition, the residue after treatment was not toxic for Vibrio fischeri bacteria.

Cloud point extraction and concentration of carbaryl from natural waters

An improved procedure is proposed for determination of the pesticide carbaryl in natural waters based on double cloud point extraction. The clean up step was carried out only with Triton X-114 in alkaline medium in order to avoid the use of toxic organic solvents as well as to minimise waste generation. Cloud point preconcentration of the product of the reaction of the analyte with p-aminophenol and cetyltrimethylammonium bromide was explored to increase sensitivity and improve the detection limit. Linear response was achieved within 10 and 500 µg L−1 and the apparent molar absorptivity was estimated as 4.6 × 105 L mol−1 cm−1. The detection limit was estimated as 7 µg L−1 at the 99.7% confidence level and the coefficient of variation was 3.4% (n = 8). Recoveries within 91 and 99% were estimated for carbaryl spiked water samples. The results obtained for natural water samples were in agreement with those achieved by the batch of spectrophotometric procedure at the 95% confidence level. The proposed procedure is then a simple, fast, inexpensive and greener alternative for carbaryl determination.

Determination of Carbaryl in River Water and Food Samples Based on the Quenching Effect on Resonance Light Scattering

A new method has been developed for the quantification of carbaryl with DNA based on a resonance light scattering technique. In the presence of carbaryl and under acidic conditions, the intensity of resonance light scattering of DNA is significantly quenched. The decrease in IRLS at this wavelength is proportional to the concentration of carbaryl. The calibration curve is linear over the range of 0.02–1.4 µg mL−1. Using this method, the recovery rates of carbaryl in river water and food samples were determined with satisfactory results. The interaction mechanism was also discussed.

Direct electrochemical determination of carbaryl using a multi-walled carbon nanotube/cobalt phthalocyanine modified electrode

The electrochemical detection of carbaryl at low potentials, in order to avoid matrix interferences, is an important challenge. This study describes the development, electrochemical characterization and utilization of a glassy carbon (GC) electrode modified with multi-wall carbon nanotubes (MWCNT) plus cobalt phthalocyanine (CoPc) for the quantitative determination of carbaryl in natural waters. The surface morphology was examined by scanning electron microscopy, enhanced sensitivity was observed with respect to bare glassy carbon and electrocatalytic effects reduced the oxidation potential to +0.80 V vs. SCE in acetate buffer solution at pH 4.0. Electrochemical impedance spectroscopy was used to estimate the rate constant of the oxidation process and square-wave voltammetry to investigate the effect of electrolyte pH. Square-wave voltammetry in acetate buffer solution at pH 4.0, allowed the development of a method to determine carbaryl, without any previous step of extraction, clean-up, or derivatization, in the range of 0.33–6.61 μmol L −1, with a detection limit of 5.46 ± 0.02 nmol L −1 (1.09 ± 0.02 μg L −1) in water. Natural water samples spiked with carbaryl and without any purification step were successfully analyzed by the standard addition method using the GC/MWCNT/CoPc film electrode.

Simultaneous Determination of Carbaryl and 1-Naphthol by First-Derivative Synchronous Non-Protected Room Temperature Phosphorescence

The applicability of non-protected room temperature phosphorescence (NP-RTP) in real samples was demonstrated in the present work. In this methodology, only two reagents, potassium iodide and sodium sulfite, were used to obtain phosphorescent signals. Overlapping of the phosphorescence spectra was resolved by using first-derivative synchronous phosphorimetry. The synchronous first-derivative spectra of carbaryl and 1-naphthol in the mixture were completely separated by changing the synchronous wavelength interval; with 240 nm the first-derivative spectra of carbaryl were recorded, while with 200 nm those of 1-naphthol appeared. The intensities in the spectra were proportional to the concentration of carbaryl and 1-naphthol. The calibration graphs were linear up to at least 1.1 x 10(-5) mol L(-1) for carbaryl and 1.3 x 10(-5) mol L(-1) for 1-naphthol, and the correlation coefficients were 0.9971 and 0.9932, respectively. Carbaryl and 1-naphthol were successfully determined by the proposed method in a hydrolyzed sample of a commercial formulation.

Halogenated molecularly imprinted polymers for selective determination of carbaryl by phosphorescence measurements

A highly selective molecularly imprinted polymer (MIP) for the recognition of the pesticide carbaryl in water has been synthesized using halogenated bisphenol A compounds as one of the polymeric precursors and carbaryl as the template molecule. On the basis of the heavy-atom effect, both the brominated and the iodinated MIPs allowed analyte detection by room-temperature-phosphorescence measurements. In the presence of an oxygen scavenger (sodium sulphite) the halide, included in the polymeric structure, induced efficient room-temperature phosphorescence of the analyte (once it had been selectively retained by the MIP). The MIP cavity can be easily regenerated for subsequent sample injections with 2 mL methanol. The optosensing system developed has demonstrated high selectivity for carbaryl, even in the presence of other luminophores that could be unspecifically adsorbed onto the MIP surface. Under optimal experimental conditions, the detection limit for the target molecule was 4 microg/L (3-mL sample injection volume), and the linear range extended up to 1 mg/L of the analyte. Good reproducibility was achieved (a relative standard deviation of 3% was obtained for ten replicates of 150 microg/L carbaryl). The synthesized sensing material showed good stability for at least 3 months after preparation. Finally, the applicability to carbaryl determination in real samples was evaluated through the successful determination of the pesticide in spiked mineral and tap water samples.

A piezoelectric immunosensor for the determination of pesticide residues and metabolites in fruit juices

A quartz crystal microbalance (QCM) immunosensor was developed for the determination of the insecticide carbaryl and 3,5,6-trichloro-2-pyridinol (TCP), the main metabolite of the insecticide chlorpyrifos and of the herbicide triclopyr. The detection was based on a competitive conjugate-immobilized immunoassay format using monoclonal antibodies (MAbs). Hapten conjugates were covalently immobilized, via thioctic acid self-assembled monolayer (SAM), onto the gold electrode sensitive surface of the quartz crystal. This covalent immobilization allowed the reusability of the modified electrode surface for at least one hundred and fifty assays without significant loss of sensitivity. The piezoimmunosensor showed detection limits (analyte concentrations producing 10% inhibition of the maximum signal) of 11 and 7 μg l −1 for carbaryl and TCP, respectively. The sensitivity attained ( I 50 value) was around 30 μg l −1 for both compounds. Linear working ranges were 15–53 μg l −1 for carbaryl and 13–83 μg l −1 for TCP. Each complete assay cycle took 20 min. The good sensitivity, specificity, and reusability achieved, together with the short response time, allowed the application of this immunosensor to the determination of carbaryl and TCP in fruits and vegetables at European regulatory levels, with high precision and accuracy.

Excitation-emission-kinetic fluorescence coupled with third-order calibration for quantifying carbaryl and investigating the hydrolysis in effluent water

A novel method for determination of carbaryl in effluent was proposed in this study. The kinetic evolution of excitation-emission matrix fluorescence (EEM) for the pesticide were recorded and come into being a four-way data array. The four-way fluorescence data were analyzed using the parallel factor analysis (PARAFAC). The methodology exploits the second-order advantage of three-order calibration based on quadrilinear parallel factor analysis, allowing analyte concentrations to be estimated even in the presence of an uncalibrated fluorescent background. It gave the satisfactory results for determination of the carbaryl in effluent samples. In addition, the kinetic study of degradation of carbaryl was performed according to the kinetic profile provided by the calibration.