Profiling cocaine residues and pyrolytic products in wastewater by mixed‐mode liquid chromatography–tandem mass spectrometry

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.

Understanding Illicit Drug Use Trends During the Carnival Holiday in the Brazilian Capital Through Wastewater Analysis

“…Higher cocaine consumption was observed in the region covered by the North-Wing WWTP compared to the region served by the South-Wing WWTP, with the exception of three isolated days. This result is consistent with findings from the last 10 years that have always shown higher cocaine use in the northern region of Brasília (Maldaner et al, 2012;Sodré et al, 2017Sodré et al, , 2018da Silva et al, 2018;González-Mariño et al, 2019).…”

“Waste Not, Want Not” — Leveraging Sewer Systems and Wastewater-Based Epidemiology for Drug Use Trends and Pharmaceutical Monitoring

“…In terms of the route of exposure, recent analysis of N, N-dimethylamphetamine in wastewater determined this to be a pyrolysis marker and synthesis impurity and indirect indicator of methamphetamine smoking. Similarly, with crack cocaine, in addition to metabolites benzoylecgonine and cocaethylene, the pyrolytic products anhydroecgonine and anhydroecgonine methyl ester are produced from the smoke of crack and are relatively stable in wastewater [ 55 ]. Like methamphetamine, cocaine use is also on the rise.…”

Trends in sample preparation and separation methods for the analysis of very polar and ionic compounds in environmental water and biota samples

“…Initially, mixed-mode columns were applied in bioanalysis, but their application was expanded to a variety of fields, including pharmaceutical analysis [88,89], metabolism studies [90,91], and recently also to environmental analysis [92][93][94][95][96][97]. González-Mariño et al [97] described the first application of RP-ion exchange mixed-mode LC for the determination of drugs of abuse in wastewater. MMLC was shown to be a good alternative to traditional RPLC and HILIC for the separation of vPICs.…”