Search results for "Benzoylurea"
showing 3 items of 3 documents
Determination of Urea Pesticide Residues in Vegetable, Soil, and Water Samples
2003
The main physico-chemical, toxicological, and environmental properties of urea pesticides are summarized. General characteristics of analytical methods for residues of phenylurea herbicides (PUHs), sulfonylurea herbicides (SUHs), and Benzoylurea insecticides (BUIs) in crops, soil, and water samples, employed in the last 5 years are reviewed. Provided it is information about liquid-liquid and solid-phase extraction of the samples and clean-up steps. The applications of gas chromatography (GC), liquid chromatography (LC), and capillary electrophoresis (CE) techniques in the analysis of these compounds are exposed in tabular form and commented on. Sensitivity and instrument conditions of liqui…
Liquid chromatography/atmospheric pressure chemical ionization-mass spectrometric analysis of benzoylurea insecticides in citrus fruits.
2000
A liquid chromatography (LC) method for the quantitative determination of three benzoylurea insecticide residues (diflubenzuron, flufenoxuron and hexaflumuron) in citrus fruits is described. Residues were successfully separated on a C18 column by methanol/water gradient elution. Detection was by negative-ion, selected-ion monitoring atmospheric pressure chemical ionization-mass spectrometry (APCI-MS); the main ions were [M - H]-, and the secondary fragment ions were [M - H - HF]-. Useful confirmatory information can thus be obtained at low extraction voltages from losses of HF. Detection limits for standard solutions were 10 fg injected and good linearity and reproducibility were obtained. …
Determination of benzoylurea insecticides in food by pressurized liquid extraction and LC-MS
2010
A method based on pressurized liquid extraction and LC-MS/MS has been developed for determining nine benzoylureas (BUs) in fruit, vegetable, cereals, and animal products. Samples (5 g) were homogenized with diatomaceous earth and extracted in a 22 mL cell with 22 mL of ethyl acetate at 80 degrees C and 1500 psi. After solvent concentration and exchange to methanol, BUs were analyzed by LC-MS/MS using an IT mass analyzer, which achieved several transitions of precursor ions that increase selectivity providing identification. LOQs were between 0.002 and 0.01 mg/kg, which are equal or lower than maximum residue limits established by the Codex Alimentarius. Excellent linearity was achieved over…