Simultaneous quantification of propranolol and sulfamethoxazole and major human metabolite conjugates 4-hydroxy-propranolol sulfate and sulfamethoxazole-β-glucuronide in municipal wastewater—A framework for multiple classes of drugs and conjugates

Abstract

Recent data suggests there are non-trivial amounts of human pharmaceutical conjugates potentially entering environmental surface waters. These compounds could contribute to eliciting toxic effects on aquatic biota either directly or indirectly, via de-conjugation. The need for developing a single method for quantifying both parents and conjugates is necessary. Propranolol (PRO), sulfamethoxazole (SMX), and their respective major conjugates 4-OH-propranolol sulfate (PRO-Sul) and sulfamethoxazole-β-glucuronide (SMX-Glc) were successfully simultaneously extracted through weak anion exchange solid phase extraction cartridges from primary and secondary clarification wastewaters from the North End Winnipeg Water Pollution Treatment Plant in Winnipeg, Canada. Subsequent separation and quantification were achieved by reversed-phase C18 chromatography coupled to positive electrospray ionisation tandem mass spectrometry. Linearity for all compounds throughout the 7-point calibration range was >0.99. Recovery RSD ranges across all matrices for PRO, SMX, PRO-Sul, and SMX-Glc were 2.1–13.2%, 2.3–10.2%, 9.8–19.2%, and 2.0–10.3% respectively. Primary and secondary filtrates respectively showed a significant increase of PRO from 0.039 to 0.045μg/L; a significant decrease for SMX from 1.56 to 0.58μg/L; significant decrease of PRO-Sul from 0.050 to 0.020μg/L; and a significant decrease of SMX-Glc from 0.41 to 0.019μg/L. These observations indicate that there was removal of all compounds, except for PRO, from the aqueous phase occurring at some point between the stages of treatment. To our knowledge, this is first study that simultaneously separated and quantified two different classes of parent compounds and two different kinds of human metabolite conjugates (glucuronide and sulfate) from a major urban wastewater treatment plant.