Characterization of metabolites in urine samples from individuals with a lethal co-administration of cocaine and ethanol

Abstract

In this paper, cocaine and eleven of its metabolites have been detected and identified in urine samples. The technique was based in a simple liquid-liquid extraction with detection by gas chromatography coupled to mass spectrometry (GC-MS). The method was validated in terms of repeatability, specificity, recovered, linearity, limit of detection, contamination between samples and robustness, all validation parameters met the acceptance criteria established in the study. The percentages of recovered for cocaine and benzoylecgonine were 120 and 110% respectively. The method’s repeatability (CV %) remained below 15% in all assays. The technique was shown to be linear over the range studied (r2 = 0.999) and sensitive, with detection limits below 60 ng/mL for both analytes. In the analysis of two real samples 11 metabolites of cocaine were detected, benzoylecgonine and cocaetilene were the majorities. Furthermore, were detected and characterized metabolites which only are observed in the urine in overdose cases such as hydroxylated and metoxyhydroxylated metabolites of cocaine, benzoylecgonine and cocaethilene. The technique allowed detecting the cinnamoilbenzoilecgonina which is a metabolite of cinnamoilcocaína. The cinnamoilcocaína is one of the alkaloids in coca plants so the presence of this metabolite showed us natural cocaine consumption and not synthetic.

Keywords

• cocaine
• cocaine´s minor metabolites
• gc-ms
• trimethylsily derivative