Multiresidue method for the rapid determination of organophosphorus insecticides in grapes, must and wine

A rapid multiresidue gas chromatographic method for determining 12 insecticides in grapes, must and wine is described. A simple on-line microextraction method for isolating frequently applied insecticides on vineyard is used. The matrix, once extracted with an acetone-dichloromethane (1:1, v/v) mixture, was filtered and concentrated. Nitrogen-phosphorus detection (NPD) and electron-capture detection (ECD) were used to identify and quantify the insecticides, the findings being confirmed using mass spectrometric detection (MSD). No clean-up was necessary for either NPD or ECD. The regression coefficients relating to linearity were at least 0.99. Recoveries from spiked grape, must and wine samples ranged from 80 to 108% and relative standard deviations were no higher than 16% in the most unfavourable case. Individual detection limits were in the range 0.02-0.1 ng. Limits of quantification varied from 0.01 to 0.05 mg kg(-1), which are below the maximum residue limits set by the legislation of the main wine-producing countries of the European Union. Only in the case of methidathion and quinalphos were the limits of quantification equivalent to the maximum residue limits (0.05 mg kg(-1)) established by Spanish and French legislation, respectively.