With rapid growth in population and advancement in chemical industries, our wastewaters contain thousands of compounds. Hence, non-targeted analysis using High Resolution Accurate Mass (HRAM) instrument is gaining traction. In addition to monitoring thousands of analytes by a targeted library search, HRAM instruments collect data on all ionizable species thus allowing retrospective data-mining to determine new and yet unknown contaminants that may become relevant.<br/>Current approach employed 1290 UHPLC and 6545 LC/QTOF with 40uL injection without sample enrichment. All Ions MSMS acquisition and a Water Screening Personal Compound Database and Library (PCDL) that contained &gt;1400 environmentally-relevant compounds were used. The PCDL contained &gt;1,000 compounds with MS/MS spectra including EPA regulated compounds, pharmaceuticals, pesticides, veterinary drugs, illicit drugs, toxins, etc. All Ions MSMS in positive and negative modes was performed at CEs 0, 20 and 40 eV, allowing simultaneous collection of precursor and fragments data. Molecular structure correlator software was used to elucidate some chemical structures for the analytes that don’t have MS/MS spectra in the PCDL. Water samples from a local treatment plant were analyzed: influent, primary effluent after coagulation, secondary effluent after sludge treatment and final effluent after NaOCl treatment. About 50 compounds were identified in influent using Water Screening PCDL. After coagulation, similar number of compounds was identified (~65% overlap) suggesting little removal of contaminants. Activated sludge treatment showed ~40% reduction of compounds, mostly for acidic organics, e.g., ibuprofen. Disinfection with NaOCl resulted in transformation by-products, e.g., dichloroacetic acid, uracil, and guanylurea. Perfluorinated acids, phthalates, metformin, valsartan, gemfibrozil, etc. survived treatments and were present in final effluent. LC-QTOF and Water Screening PCDL are of great value for comprehensive water quality monitoring. The All Ions MSMS acquisition allows confident analytes identification by fragments and retrospective data mining for new entities.

Organic contaminants monitoring during water treatments by UHPLC-HRAM: From influent to effluents

253rd National Meeting (2017)

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