Determination Of Acephate Research Articles

Determination of Acephate in Vegetables by Magnetic Molecularly Imprinted Polymer Isolation Coupled with High-Performance Liquid Chromatography

Magnetic molecularly imprinted polymers based on carbon nanotubes were prepared and characterized by infrared spectrometry, transmission electron microscopy, and vibrating sample magnetometry and were employed for the isolation of acephate from cabbage, spinach, lettuce, leeks, and celery. Kinetic and recognition studies were carried out in order to investigate the adsorption properties of the polymers. During the application process, the acephate extracted from vegetables was purified with the magnetic molecularly imprinted polymers and determined by high performance liquid chromatography with an ultraviolet detector. The recoveries of acephate at three fortified concentrations (0.015, 0.15, and 1.5 mg kg−1) were between 89.2% and 93.4%. The limits of detection and quantification of acephate were 0.0025 and 0.0077 mg kg−1, respectively. The linear dynamic range was from 0.01 to 5 mg kg−1. The relative standard deviations of intra- and inter-day precision were 1.1% to 5.9% and 2.7% to 6.4%, respectively. The developed method was demonstrated to be rapid and selective for the extraction and determination of acephate in vegetables.

Ultrasonic accelerated removal and determination of acephate on poly(GMA/DVB) using HPLC method

Ultrasonic accelerated removal and determination of acephate on poly(GMA/DVB) using HPLC method

Determination of Acephate in Human Urine

Acephate is a commonly used organophosphate insecticide applied on agricultural crops and in residential communities. Because very little acephate is metabolized prior to excretion, the parent pesticide compound can be measured in human urine. The residue method must be sensitive enough to determine human exposure and potential health risk for both agricultural workers and their families who may be exposed by pesticide drift or by inadvertent carry-home residues. A reliable and sensitive method was developed to measure acephate concentrations in human urine. Urine was diluted with water and acetone, adjusted to a neutral pH, and partitioned twice in acetone-methylene chloride (1 + 1, v/v), with NaCl added to aid separation. The solvent-reduced organic phase extracts were clarified by activated charcoal solid-phase extraction and then adjusted to a final volume with the addition of a D-xylose analyte protectant solution to reduce matrix enhancement effects. Acephate concentrations in urine were determined by gas chromatography using pulsed flame photometric detection. The method limit of detection was established at 2 microg/L, with a method limit of quantitation of 10 microg/L. The average recovery from urine fortified with 10-500 microg/L was 102 +/- 12% (n = 32).

Determination of acephate and its degradation product methamidophos in soil and water by solid-phase extraction (SPE) and GC-MS

Acephate and its metabolite, methamidophos, are both highly polar organophosphorus pesticides (OPs) and are therefore highly soluble in water, which leads to difficulties when traditional methods of extraction, such as LLE (liquid–liquid extraction), are used. Solid-phase extraction (SPE) is a relatively new, highly versatile method, which has proven successful in many cases that were considered problematic in the past. In this study, several adsorbents (polymeric and silica based) and parameters are considered and modified to obtain maximum recovery. Maximum recoveries for acephate and methamidophos were found to be 90–95% and 85–90% respectively with Oasis HLB cartridges and methylene chloride as the elution solvent. In order to establish applicability and reliability, the matrix effect of several real water and solid (compost and soil) samples was evaluated. A 20–30% diminution of recovery is noted for some samples with a complex matrix containing a high amount of dissolved organic matter.

Multiresidue Method for Quantitative Gas Chromatographic Determination of Pesticide Residues in Sweet Cherries

Abstract A multiresidue method is described for determination of acephate, diazinon, dimethoate, fenitrothion, malathion, pirimicarb, trichlorfon, bromopropylate, dicofol, and tetradifon in sweet cherries for baby food at a limit of 0.01 ppm. Sweet cherry samples were extracted through a selective Extrelut column with methylene chloride and cleaned up with quaternary aminesilane-silica-dichloromethane. Extracts were then analyzed by gas chromatography (GC)/electron capture detection/flame photometric detection (FPD) and GC/nitrogen-phosphorous detection/FPD. Recoveries were determined by spiking sweet cherry homogenates with 10 pesticides at 0.1, 0.05, 0.02, and 0.01 ppm. Six determinations were performed at each level for each pesticide. Recoveries were 70% or better at the 0.01 ppm level.

Determination of Acephate and Methamidophos in Foods Using Super-absorbent Polymer

H. Obana, M. Okihashi, S. Kakimoto and S. Hori, Anal. Commun., 1997, 34, 253 DOI: 10.1039/A704952H

Determination of methamidophos residues in food remnants.

Over the past 7 years, acute food poisoning arising from the consumption of methamidophos-tainted vegetables has occurred sporadically in Hong Kong. To enable prompt remedial and regulatory actions to be taken, a simple and rapid gas chromatographic method was developed to determine methamidophos residues in food remnants. Samples were homogenized and extracted with acetone. Acetone in the resultant extract was removed by rotary evaporation, leaving behind an aqueous solution. After washing with petroleum ether and addition of sodium sulphate, the aqueous solution was re-extracted with chloroform. The chloroform extract was concentrated to dryness and the residue was reconstituted in absolute ethanol for determination by gas chromatography with flame photometric detection. The method was found to be applicable also to the determination of acephate, dimethoate, omethoate and trichlorfon. Mean recoveries of the five organo-phosphorus pesticides at two fortification levels, viz. 1 mg/kg and 10 mg/kg, ranged from 74 to 113%. Relative standard deviations lay between 1.3 and 6.1%. Method detection limits ranged from 0.02 to 0.04 mg/kg. In 1994, 75 food poisoning cases in Hong Kong were suspected to be related to the consumption of methamidophos-tainted vegetables; 13 food remnants were received for analysis, four of them were found to contain high concentrations of methamidophos.

Determination of Acephate in Water by Solid-phase Extraction/Gas Chromatography.

Solid-phase extraction of acephate in natural water was studied using ODS-cartridge. 250 ml of sample water to which 25 g of ammonium sulfate was added was passed through the cartridge at a flow rate of 10 ml/min. The cartridge was dried with dry air. Acephate was eluted with 10 ml of methanol. After removing the solvent from the eluate, 1 ml of acetone was added to the residue and determined by gas chromatograph with a flame thermionic detector. The recovery of acephate added to river water was in the range of 84-90%. The coefficient of variation was less than 7%. The limit of detection was 1 μg/l. By the proposed method, the concentration of acephate in river and lake waters, which were used for water supply in Ibaraki, was determined through the year. No acephate were detected in any water samples.