The Supercritical Fluid Extraction of Drugs of Abuse from Human Hair

The presence in the body of drugs of abuse can be identified by a variety of laboratory procedures. The standard in drug testing is the immunoassay screen, followed by a gas chromatography/mass spectrometry (GC/MS) confirmation conducted on a urine sample. In general, drug concentrations in urine can be determined only when exposure to the drugs occurs 2–4 d before sample collection. In recent years, remarkable advances in sensitive analytical techniques have enabled the analysis of drugs in unconventional biological samples such as hair. Since 1979, hair has been used to document chronic human drug exposure (1 ). To date, more than 400 articles concerning hair analysis have been published (2 ), with applications in clinical (3 ) and forensic (4 ) toxicology.