Liquid chromatography mass spectrometry and high-resolution Fourier transform ion cyclotron resonance mass spectrometry (LC/ESI-FT-ICR-MS) for identifying photodegradation products of pharmaceuticals in the aquatic environment

Many pharmaceuticals (PhCs) are considered as emerging contaminants [1] introduced anthropogenically in the environment through industry or domestic wastewater [2]. PhCs have been detected at parts per million and parts per trillion concentrations in surface waters suggesting an inefficient removal of these compounds by conventional sewage treatment processes. Liquid chromatography/mass spectrometry (LC/MS) has become a powerful technology for the monitoring, characterization and identification of PhCs residues [3,4]. In this work the formation of main photoproducts arising from the photolysis and photocatalysis (TiO2) reactions of some PhCs in water (0.5 mg/L) was monitored, and their structures were proposed by exact mass determinations. All photoproducts (photolysis and photocatalysis) have been successfully identified using LC/ESI-FTICR-MS in positive or negative mode.  Accurate masses were obtained and molecular formulae were proposed on the basis of known photochemical pathways and the structure of the mother molecules. Results contributed to enhance the knowledge about the environmental fate of pharmaceuticals investigated.