Gc-Orbitrap-Ms Strategy for Micropollutants Screening in Ozone Treated Wastewaters

In this study we develop a methodology for the comprehensive characterization of semivolatile organic pollutants in secondary wastewater effluents and in ozone treated waters. Gas chromatography coupled to Orbitrap mass spectrometry (GC-Orbitrap-MS) was optimized in a step-wise procedure where: (i) the TraceFinder 4.1 deconvolution software parameters were adjusted to define detection criteria and (ii) retention time alignment, accurate mass spectral information and ranked library hits were set for untargeted screening. The optimized conditions were tested and validated with a set of 59 standard compounds. Finally, raw and ozone-treated effluent samples were processed with the developed strategy to determine the removal of phthalates, organophosphate flame retardants and other compounds identified with untargeted screening. A comparison between the removal rates using both target and untargeted screening analysis methodologies was performed and a good agreement was observed in most of cases. The proposed workflow methodology enhances the analytical capability to monitor water contaminants and optimize ozone doses to ensure the efficiency of water treatment works.