Dimethoate degradation in plants and during processing of yerba maté leaves

Abstract

The objective of this research was to study degradation kinetics of dimethoate in plants of Ilex paraguariensis Saint Hilaire (or yerba maté) and during its processing. To determine dimethoate concentration, a capillary gas chromatography technique with a mass selective detector was used. Half-life times in plants ranked between 9.8 and 11.8 days. During processing, with a blanching and two drying steps, dimethoate concentration decayed to a 22.7% of its initial value (in dry basis); while during seasoning step (at 45°C), half-life time was 17.3 days. With these values, preharvest safety interval was determined.