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Shokuhin Eiseigaku Zasshi. Journal of... 2017An analytical method based on LC-MS/MS was developed for the determination of formetanate hydrochloride in agricultural products. Formetanate hydrochloride was confirmed...
An analytical method based on LC-MS/MS was developed for the determination of formetanate hydrochloride in agricultural products. Formetanate hydrochloride was confirmed to be stable in acetonitrile. It was therefore extracted from samples with acetonitrile, and the crude extracts were purified using a combination of ethylenediamine-N-propyl silylation silica gel and graphite carbon mini columns. Formetanate hydrochloride in the resulting sample solutions was quantified by LC-MS/MS utilizing an external solvent calibration curve. The average recovery (n=5) of formetanate hydrochloride spiked in 10 types of agricultural products (brown rice, soybean, spinach, cabbage, potato, apple, orange, lime, nectarine and green tea) at the maximum residue limits (MRLs) or at a uniform limit of 0.01 mg/kg was 92.3-103%, with a relative standard deviation of 1.3-5.4%. The limit of quantitation of the developed method was calculated to be 0.01 mg/kg.
Topics: Acetonitriles; Carbamates; Chromatography, Liquid; Crops, Agricultural; Food Analysis; Pesticide Residues; Solutions; Tandem Mass Spectrometry
PubMed: 29081458
DOI: 10.3358/shokueishi.58.221 -
Bioelectrochemistry (Amsterdam,... Aug 2014A bi-enzymatic biosensor (LACC-TYR-AuNPs-CS/GPE) for carbamates was prepared in a single step by electrodeposition of a hybrid film onto a graphene doped carbon paste...
A bi-enzymatic biosensor (LACC-TYR-AuNPs-CS/GPE) for carbamates was prepared in a single step by electrodeposition of a hybrid film onto a graphene doped carbon paste electrode (GPE). Graphene and the gold nanoparticles (AuNPs) were morphologically characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, dynamic light scattering and laser Doppler velocimetry. The electrodeposited hybrid film was composed of laccase (LACC), tyrosinase (TYR) and AuNPs entrapped in a chitosan (CS) polymeric matrix. Experimental parameters, namely graphene redox state, AuNPs:CS ratio, enzymes concentration, pH and inhibition time were evaluated. LACC-TYR-AuNPs-CS/GPE exhibited an improved Michaelis-Menten kinetic constant (26.9±0.5M) when compared with LACC-AuNPs-CS/GPE (37.8±0.2M) and TYR-AuNPs-CS/GPE (52.3±0.4M). Using 4-aminophenol as substrate at pH5.5, the device presented wide linear ranges, low detection limits (1.68×10(-9)±1.18×10(-10)-2.15×10(-7)±3.41×10(-9)M), high accuracy, sensitivity (1.13×10(6)±8.11×10(4)-2.19×10(8)±2.51×10(7)%inhibitionM(-1)), repeatability (1.2-5.8% RSD), reproducibility (3.2-6.5% RSD) and stability (ca. twenty days) to determine carbaryl, formetanate hydrochloride, propoxur and ziram in citrus fruits based on their inhibitory capacity on the polyphenoloxidases activity. Recoveries at two fortified levels ranged from 93.8±0.3% (lemon) to 97.8±0.3% (orange). Glucose, citric acid and ascorbic acid do not interfere significantly in the electroanalysis. The proposed electroanalytical procedure can be a promising tool for food safety control.
Topics: Biosensing Techniques; Carbamates; Carbon; Chitosan; Electrodes; Gold; Graphite; Hydrogen-Ion Concentration; Laccase; Microscopy, Electron, Transmission; Monophenol Monooxygenase; Nanoparticles; Oxidation-Reduction; Pesticides; Photoelectron Spectroscopy; Sensitivity and Specificity; Surface Properties
PubMed: 24642204
DOI: 10.1016/j.bioelechem.2014.02.003