Quantification of typical antiviral drugs in wastewater and sludge from WWTPs using high-performance liquid chromatography-tandem mass spectrometry

In this study, the analysis methods for 7 typical antiviral drugs in wastewater and sludge were established using solid-phase extraction and ultrasonic extraction combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and the pre-treatment process and the parameters of chromatography and mass spectrometry were optimized. The wastewater samples were treated by filtration and pH adjustment, and then subjected to solid-phase extraction, nitrogen-blowing evaporation and re-dissolution. The sludge samples were added into extraction solutions, and then subjected to ultrasonication, centrifugation, nitrogen-blowing evaporation and re-dissolution. The re-dissolved samples were analyzed on a HPLC-MS/MS and quantified by internal standard method. The optimized results were as follows: the standard curves for the 7 target drugs exhibited excellent linearity (R² > 0.999), the spiked recoveries of water and sludge samples ranged from 90.40% to 117.80% and 88.94% to 117.87%, respectively. The instrumental limits of quantification (LOQ) ranged from 0.032 µg·L−1 to 1.026 µg·L−1, while the limits of detection (LOD) ranged from 0.010 µg·L−1 to 0.308 µg·L−1, with precision values were between 0.07% and 9.49%. The method had high accuracy, stability, and sensitivity, and could meet the demand of high sensitivity detection of drug residues in wastewater and sludge. The method was applied to analyze influent, effluent and activated sludge from a wastewater treatment plant in Shanghai. The results shown that, with the exception of Budesonide, the remaining 6 target drugs were detected in influent and effluent, and their concentration might correlate with seasonal patterns of drug usage, disease outbreaks, and environmental factors; The remaining 6 target drugs were also detected in activated sludge. This study provided a research basis for assessing and controlling the environmental risks of antiviral drugs in municipal wastewater treatment plants.