Determination of fenthion and oxidation products in personal protection equipment by gas chromatography

A method for the co-extraction and simultaneous chromatographic determination of fenthion and its five oxidation products (or metabolites) fenoxon, fenoxon–sulfoxide, fenoxon–sulfone, fenthion–sulfoxide, and fenthion–sulfone in personal protection equipment (PPE) of pesticide applicators was developed and validated. Capillary gas chromatography–nitrogen–phosphorus detection was used for the analytical determination of all the aforementioned compounds over the concentration range of 0.1–0.5 μg/mL. All necessary validation criteria of the method were met. The method was found to be highly selective, accurate, and precise, gave satisfactory recovery (>70%) and RSD values (<20%) for fenthion and its metabolites in all tested specimens of personal protection equipment and in air samplers. The limit of quantification (LOQ) and linearity were determined for the most relevant PPE (i.e. inner coverall) for the parent compound and for the metabolites. The LOQ values ranged from 0.05 to 0.1 ppb while the linearity in the tested range of 0.1–0.5 ppm had r2 > 0.994 for all analytes.