Norcocaine and cocaethylene distribution patterns in hair samples from light, moderate, and heavy cocaine users

Cristiana Gambelunghe, Riccardo Rossi, Kyriaki Aroni, Alessio Gili, Mauro Bacci, Vincenzo Lorenzo Pascali, Nadia Fucci

Risultato della ricerca: Contributo in rivistaArticolo in rivista

17 Citazioni (Scopus)


Even though hair analysis often seems to be the best choice for retrospective monitoring of cocaine intake, differentiating between incorporated cocaine and external contamination is widely debated. In this study we report results obtained in 90 hair samples from addicts. All samples were analyzed for cocaine, benzoylecgonine, norcocaine, cocaethylene, and tropococaine by gas chromatography-mass spectrometry (GC-MS) techniques coupled with direct immersion solid-phase micro-extraction. Cocaine concentrations were stratified into three classes of usage: light (0.5-3 ng/mg), moderate (3.1-10 ng/mg) and heavy (10.1-40 ng/mg). The Substance Abuse and Mental Health Services Administration cut-off criteria for establishing active cocaine use were applied to the results. For all samples criteria were cocaine levels above 0.5 ng/mg (ranging from 1.63 to 39.29 ng/mg, mean 9.49 ng/mg), benzoylecgonine concentrations ≥ 0.05 ng/mg (ranging from 0.19 to 5.77 ng/mg, mean 1.40), and benzoylecgonine to cocaine % ratio ≥5% (from 6.43 to 26.09%). Norcocaine was present in 58.9% of samples (concentration range: 0.22-3.14 ng/mg) and was strongly predictive only of heavy cocaine use (sensitivity 100% for cocaine concentrations above 9.58 ng/mg). Twenty hair samples from moderate and heavy users tested positive for cocaethylene (concentration range: 0.22-1.98 ng/mg, mean 0.73 ng/mg). This study on hair samples with no chance of false positive cases highlights the very limited applications of testing minor cocaine metabolites for definitive proof of active cocaine consumption.
Lingua originaleEnglish
pagine (da-a)161-167
Numero di pagine7
RivistaDrug Testing and Analysis
Stato di pubblicazionePubblicato - 2017


  • 3003
  • Analytical Chemistry
  • Cocaethylene
  • Cocaine
  • Environmental Chemistry
  • Hair analysis
  • Norcocaine
  • Spectroscopy


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