Determination of N-methylcarbamate pesticides using flow injection with photoinduced chemiluminescence detection

Abstract

A sensitive, economic, rapid and simple method for the determination of four N-methylcarbamate pesticides: methomyl (2.0–80 μg L−1), aldicarb (5.0–50 μg L−1), butocarboxim (2.0–60 μg L−1) and oxamyl (2.0–60 μg L−1); is reported. It relies on the coupling of photoinduced chemiluminescence (PICL) detection with flow injection (FI) methodology. The automation of FI together with the use of light as a reagent decreased the environmental impact of the analysis. The proposed method was based on the oxidation of these pesticides, previously irradiated on-line with UV light, with cerium(IV), using quinine as a sensitiser. Limits of detection below the legal limits (100 ng L−1) established by the European Union for drinking waters were obtained without the need of preconcentration steps. A good inter-day reproducibility (1.6–6.4%, n = 5), repeatability (rsd = 2.7 %, n = 25) and high throughput (123 h−1) were achieved. The method was successfully applied to the determination of methomyl in natural waters with mean recoveries ranging from 90% to 98%.