Hair testing for cocaine and metabolites by GC/MS: criteria to quantitatively assess cocaine use
Article first published online: 9 MAR 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Journal of Applied Toxicology
Volume 33, Issue 8, pages 838–844, August 2013
How to Cite
López-Guarnido, O., Álvarez, I., Gil, F., Rodrigo, L., Cataño, H. C., Bermejo, A. M., Tabernero, M. J., Pla, A. and Hernández, A. F. (2013), Hair testing for cocaine and metabolites by GC/MS: criteria to quantitatively assess cocaine use. J. Appl. Toxicol., 33: 838–844. doi: 10.1002/jat.2741
- Issue published online: 21 JUN 2013
- Article first published online: 9 MAR 2012
- Manuscript Revised: 24 JAN 2012
- Manuscript Accepted: 24 JAN 2012
- Manuscript Received: 21 DEC 2011
- hair testing;
- interpretation of results
A simple, rapid and sensitive method has been developed and validated for the determination of cocaine and its main metabolites (benzoylecgonine and cocaethylene) in human hair. The method involved solid-phase extraction with an Oasis HLB extraction cartridge and subsequent analysis by GC/MS. The limit of detection was 0.01 ng mg−1 for cocaine, 0.04 for benzoylecgonine and 0.03 for cocaethylene. The method validation included linearity (with a correlation coefficient >0.99 over the range 0.2–50 ng mg−1), intra- and inter-day precision (always lower than 12%) and accuracy (mean relative error always below 17%) to meet the bioanalytical acceptance criteria. The procedure was further applied to 40 hair samples from self-reported cocaine users arrested by the police who provided a positive urine-analysis for cocaine, and was demonstrated to be suitable for its application in forensic toxicology. New approaches were raised to detect false-negative results that allow a better interpretation of hair testing results. Copyright © 2012 John Wiley & Sons, Ltd.