Examination of the degradation of drugs in municipal sewage plants using liquid chromatography-electrospray mass spectrometry

Numerous drugs can be identified in the secondary effluent of municipal sew age plants. in order to obtain information about the degree of elimination (adsorption, aerobic degradation) of these compounds, a batch reactor conta ining different drugs in environmentally relevant concentrations and a susp ension of activated sludge was coupled to a HPLC-MS-MS system. During a tes ting period of three days concentration-time-curves were recorded. For most of the examined drugs (acetamidoantipyrine? crotamiton, diclofenac, primid one. propyphenazone) solely a strong decrease of the initial concentration within the first 15 minutes was observed, which was interpreted primarily a s adsorption to the activated sludge. For acetaminophenol and pentoxifyllin an additional slower decrease in concentration within several hours was ob served. This slower elimination was interpreted to be caused mainly by prim ary degradation, It could be shown that dihydrocodeine is oxidized to hydro codone in the batch reactor. The conjugate acetaminophen glucuronide was cl eaved.