A novel direct solid pyrolysis coupled microplasma optical emission spectrometry for rapid determination of dithiocarbamates in food samples.

Abstract

Dithiocarbamates (DTCs), widely used fungicidal pesticides, are conventionally detected via a cumbersome 2-h derivatization process that converts them into CS2 for gas chromatography, which is susceptible to leakage and poor reproducibility. Herein, we propose a novel and rapid detection method that improves throughput and simplifies operation. Solid samples are directly introduced into a tubular furnace without pretreatment and reagents. DTCs are pyrolyzed within 30 s to release characteristic CS2 gas, which is then excited by a point discharge microplasma and detected in real time at 257.56 nm using a handheld optical emission spectrometer. The method exhibits good linearity (R2 > 0.99) in the range of 0.01-0.1 mg, with a detection limit of 3.5 μg. Matrix effects are corrected using matrix-matched calibration, yielding spiked recoveries of 87-107% with RSDs of 2.3-7.6%. Operating at atmospheric pressure, the system offers a rapid and reliable approach for DTC detection in solid food samples.