Search for conjugated drug metabolites in surface water and during drinking water treatment

Résumé : Pharmaceuticals for human or veterinary use are found, by various means, in aquatic environments and particularly in drinking water treatment plants. Pharmaceuticals are partially metabolized after ingestion (the percentage depends on the parent drug and falls between 1 and 99%), and consequently pharmaceuticals can be found in drinking water at concns. ranging from the ng·L-1 to hundreds of ng·L-1. Different types of metabolites exist, among them conjugates that can represent up to 90% of the released metabolites of a pharmaceutical. The present work describes the development of an anal. method using "online Solid Phase Extn." (SPE) - high performance liq. chromatog. - tandem mass spectrometry (LC-MS/MS) for the detn. and quantification of the active substances and their conjugates in surface waters and during drinking water treatment. These conjugates may be subjected to a deconjugation during treatment, resulting in the release of the parent pharmaceutical. Hence, it is necessary to focus on these mols. and in particular on the glucuronide conjugates. As all stds. are not com. available, a new synthetic route in an aq. medium has been explored. Analyses are performed on the input and output of drinking water treatment plants to det. the concns. of parent drugs and their conjugates. The obtained limits of detection and quantification are in the order of 1 to 10 ng·L-1.