González Mariño, IriaEstévez-Danta, AndreaRodil Rodríguez, María del RosarioSilva, Katyeny Manuela daSodré, Fernando FabrizCela Torrijos, RafaelQuintana Álvarez, José Benito2020-01-212020-03-192019-03-19González‐Mariño, I, Estévez‐Danta, A, Rodil, R, et al. Profiling cocaine residues and pyrolytic products in wastewater by mixed‐mode liquid chromatography–tandem mass spectrometry. Drug Test Anal. 2019; 11: 1018– 1027. https://doi.org/10.1002/dta.2590http://hdl.handle.net/10347/20587This is the peer reviewed version of the following article: González‐Mariño, I, Estévez‐Danta, A, Rodil, R, et al. Profiling cocaine residues and pyrolytic products in wastewater by mixed‐mode liquid chromatography–tandem mass spectrometry. Drug Test Anal. 2019; 11: 1018– 1027, which has been published in final form at https://doi.org/10.1002/dta.2590. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsThis work provides a new analytical method for the determination of cocaine, its metabolites benzoylecgonine and cocaethylene, the pyrolytic products anhydroecgonine and anhydroecgonine methyl ester, and the pharmaceutical levamisole in wastewater. Samples were solid‐phase extracted and extracts analyzed by liquid chromatography–tandem mass spectrometry using, for the first time in the illicit drug field, a stationary phase that combines reversed‐phase and weak cation‐exchange functionalities. The overall method performance was satisfactory, with limits of detection below 1 ng/L, relative standard deviations below 21%, and percentages of recovery between 93% and 121%. Analysis of 24‐hour composite raw wastewater samples collected in Santiago de Compostela (Spain) and Brasilia (Brazil) highlighted benzoylecgonine as the compound showing the highest population‐normalized mass loads (300–1000 mg/day/1000 inhabitants). In Brasilia, cocaine and levamisole loads underwent an upsurge on Sunday, indicating a high consumption, and likely a direct disposal, of cocaine powder on this day. Conversely, the pyrolytic product resulting from the smoke of crack, anhydroecgonine methyl ester, and its metabolite anhydroecgonine were relatively stable over the four days, agreeing with a non‐recreational‐associated use of crackeng© 2019 John Wiley & Sons, Ltd.Crack cocaineReversed‐phase ion‐exchange liquid chromatographySewageSolid‐phase extractionTandem mass spectrometryjournal article10.1002/dta.25901942-7611open access