Monitorization of ibuprofen, diclofenac and triclosan and their photolytic transformation products

• Degradation of emerging contaminants by direct photolysis by UVA irradiation. • Microextraction of contaminants and photoproducts by in situ generated ionic liquid. • Application of untargeted strategies for transformation products identification. The presence of contaminants of emerging concern (CECs) in wastewater treatment plant (WWTP) effluents poses a significant risk to human health and the environment. The application of photolytic processes in remediation of WWTP effluents results in the formation of transformation products (TPs) with unknown environmental impact. Thus, the identification of TPs and the monitoring of their evolution during the remediation process is of great interest. This study presents a new analytical method for the determination of three CECs (ibuprofen, IBU; diclofenac, DCF; triclosan, TCS) and their respective TPs in water subjected to direct photolysis by ultraviolet A irradiation with light emitting diode lamps. The analytes were extracted using in situ ionic liquid dispersive liquid–liquid microextraction and analysed by liquid chromatography with high resolution mass spectrometry (LC-HRMS) for the identification of known and unknown TPs. The identification of TPs was conducted through two untargeted strategies: a suspect screening based on the utilization of a home-made database created from the TPs previously described, and a screening for novel TPs based on the spectral investigation of a deconvoluted and aligned list of peaks with suitable degradation trends. The proposed analytical strategy allowed up to 39 TPs being identified, with 10 of them being structurally proposed for the first time in this study. In addition, verification of the identified TPs was carried out by LC with triple quadrupole. Moreover, the three CECs and their TPs were monitored in four WWTP samples subjected to degradation trials and two TPs (DCF-TP296 C and TCS-TP303 C ) were found.