Profiling cocaine residues and pyrolytic products in wastewater by mixed‐mode liquid chromatography–tandem mass spectrometry. Issue 7 (23rd April 2019)

• Record Type: Journal Article
• Authors: González‐Mariño, Iria; Estévez‐Danta, Andrea; Rodil, Rosario; Da Silva, Katyeny Manuela; Sodré, Fernando Fabriz; Cela, Rafael; Quintana, José Benito
• Is Part Of: Drug testing and analysis. Volume 11:Issue 7(2019)
• Page Start: 1018
• Page End: 1027
• Publication Date: 2019-04-23
• Subjects: crack cocaine -- reversed‐phase ion‐exchange liquid chromatography -- sewage -- solid‐phase extraction -- tandem mass spectrometry; Drugs -- Analysis -- Periodicals; Drug testing -- Periodicals; Chemistry, Forensic -- Periodicals; 615.1901
• DOI: 10.1002/dta.2590
• Languages: English
• ISSNs: 1942-7603

Abstract

Abstract: 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. Abstract : Mixed‐mode reversed‐phase ion‐exchange liquid chromatography coupled to tandem mass spectrometry was used to determine cocaine, its metabolites and pyrolytic products in wastewater. Combined with solid‐phase extraction, the method provided a satisfactory overall performance with limits of detection below 1 ng/L. The analysis of 24‐h composite raw wastewater samples from Santiago de Compostela (Spain) and Brasilia (Brazil) allowed to get insights into cocaine prevailing intake pathways, adulteration and co‐consumption with alcohol.