RT Journal Article T1 Profiling cocaine residues and pyrolytic products in wastewater by mixed‐mode liquid chromatography–tandem mass spectrometry A1 González Mariño, Iria A1 Estévez-Danta, Andrea A1 Rodil Rodríguez, María del Rosario A1 Silva, Katyeny Manuela da A1 Sodré, Fernando Fabriz A1 Cela Torrijos, Rafael A1 Quintana Álvarez, José Benito K1 Crack cocaine K1 Reversed‐phase ion‐exchange liquid chromatography K1 Sewage K1 Solid‐phase extraction K1 Tandem mass spectrometry AB This 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 crack PB Wiley YR 2019 FD 2019-03-19 LK http://hdl.handle.net/10347/20587 UL http://hdl.handle.net/10347/20587 LA eng NO 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. https://doi.org/10.1002/dta.2590 NO This 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 Versions NO This work was financially supported by Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia (ED431C2017/36 and IGM postdoctoral contract, Plan Galego I2C‐Modalidade B, ED481D 2017/003), Ministerio de Economía y Competitividad (project no. CTM2017‐84763‐C3‐2‐R), the Federal District Research Foundation (project no. 193.000.916/2015), and FEDER/ERDF DS Minerva RD 29 abr 2026