Chemiluminescence of dithiocarbamate fungicides based on the luminol reaction

Abstract

The chemiluminescence of luminol with dithiocarbamate fungicides (ziram, mancozeb and propineb) was examined by flow injection analysis (FIA). It was found that chemiluminescence was directly produced by the reaction of dithiocarbamate fungicides with luminol in the presence of a catalyst in an alkaline solution. Hexacyanoferrate(III) as catalyst/cooxidant and hexacyanoferrate(II) as depressor were used for the reaction. To explain the mechanism of the chemiluminescence of luminol with dithiocarbamate fungicides, electron spin resonance (ESR) measurements were performed. ESR showed that hydroxyl radicals were generated from dithiocarbamate fungicides in the alkaline solution by using 5,5′-dimethyl-1-pyrroline N-oxide as a spin trap agent. Detection limits (S/N=3) of ziram, mancozeb and propineb were 2.0, 0.1 and 0.5 ppb (milliard 1,000,000,000), respectively.