Determination of Pharmaceutical Drug Residues on Suspended Particulate Material in Surface Water

Recent studies have demonstrated the presence of traces of various pharmaceutical drugs in the aquatic environment. Comprehensive data about the distribution of such compounds between the aqueous phase and suspended particulate material are still missing. In the present article a gas chromatographic method with mass spectrometric detection is presented which allows the determination of the particle-bound fraction of some pharmaceuticals commonly found in surface water. Determination limits are between 2 and 12 ng/g particles. Results from surface water samples indicate the possibility that less hydrophilic pharmaceuticals like mefenamic acid are present as suspended particulate material, although the amounts are small in comparison with the concentrations found in aqueous phase. Additional work will be necessary to evaluate the full importance of particle-bound pharmaceuticals with respect to transportation in the environment.