Comparison of an acetonitrile extraction/partitioning and "dispersive solid-phase extraction" method with classical multi-residue methods for the extraction of herbicide residues in barley samples.

Does further clean-up reduce the matrix enhancement effect in gas chromatographic analysis of pesticide residues in food?

Determination of 3 neonicotinoid insecticides, nitenpyram, imidacloprid, and acetamiprid, was studied. Vegetables and fruits were extracted with acetonitrile. The crude extract was passed through a weak anion-exchange cartridge (PSA). The effluent was subjected to silica gel cartridge. Imidacloprid and acetamiprid were eluted with 10 mL of 4:6 (v/v) acetone/hexane, followed by nitenpyram with acetone (20 mL). Pesticides were determined by HPLC with a C-18 column and diode-array detection system. Imidacloprid and acetamiprid were recovered at about 90% at the spike levels with 0.2 and 2 mg/kg in cucumber, potato, tomato, eggplant, Japanese radish, and grape. Nitenpyram was recovered at 64-80%. Relative standard deviations were less than 10% throughout all the recovery tests. In the residue analysis, agriculturally incurred pesticides at 0.08-0.14 mg/kg were designated with UV spectra compared with respective reference standards.

Determination of acetamiprid, imidacloprid, and nitenpyram residues in vegetables and fruits by high-performance liquid chromatography with diode-array detection.

Simultaneous screening for 238 drugs in blood by liquid chromatography–ionspray tandem mass spectrometry with multiple-reaction monitoring

Analytical methods to determine phosphonic and amino acid group-containing pesticides

A method is described for determining 199 pesticides in fruit and vegetables. Residues are extracted from samples with acetonitrile, and coextractives are removed with a miniaturized charcoal-Celite column cleanup. Analysis is performed by gas chromatography with mass-selective detection in selective-ion monitoring mode. Two injections per sample are required to cover all compounds. Positive analytes are confirmed by retention time and ion ratios. Carbamates are analyzed by liquid chromatography with postcolumn reaction and fluorescence detection. Recovery data were obtained by fortifying 3 matrixes (pears, carrots, and bananas) at 0.1-0.5 ppm. In addition, the method demonstrated acceptable performance for analysis of other crops such as apple, strawberry, orange, pineapple, asparagus, beet, cucumber, tomato, pepper, squash, green peas, potato, and sweet potato. Limits of detection ranged from 0.02 to 0.2 ppm depending on the compound.

Multiresidue determination of pesticides in fruit and vegetables by gas chromatography-mass-selective detection and liquid chromatography with fluorescence detection

Mario Lacrolx

Papers

Multiresidue determination of pesticides in fruit and vegetables by gas chromatography-mass-selective detection and liquid chromatography with fluorescence detection