MATRIX EFFECTS IN THE DETERMINATION OF ACARICIDES AND FUNGICIDES IN MUST BY GAS-CHROMATOGRAPHY WITH ELECTRON-CAPTURE AND NITROGEN-PHOSPHORUS DETECTION

The gas chromatographic determination of 12 pesticides, often used in viticulture, usually presents higher values than the real ones, arisin g from matrix effects, when must samples are analyzed. In order to red uce those errors, a method involving solid-phase extraction on octadec ylsilane cartridges followed by a Florisil clean-up is developed. More over, a calibration with must extracts containing increasing amounts o f pesticides and subjected to the same treatment as the samples also c ontributes to diminishing such errors. (C) 1997 Elsevier Science B.V.