Rapid chromatographic methods for the identification and determination of chlorophenoxy herbicides

Derivatives of chlorophenoxy carboxylic acids have been the first class of herbicides in continuous use since 1947. The main interest for these substances is due to their evident chronic toxicity and carcinogenic effect. On the other hand, they can cause acute toxicity and have significant role in suicidal attempts. In this paper we have investigated analytical approaches that could be used for rapid identification and determination of chlorophenoxy herbicides in modestly equipped laboratories for the clinical toxicology. Thin layer chromatography on cellulose layer using neutral red as ion pairing reagent gave the best results in separation of different herbicides, making possible visualisation at the daylight without further reagents or equipment. High performance liquid chromatography (HPLC) methods for separation on C8 and C18 phases with and without ion-pairing reagent were compared. It was found that HPLC on C18 phase utilising ion-suppression mode has the best reproducibility, linearity and mass limit of detection suitable for quantification of chlorophenoxy herbicides after acute poisoning.