An evaluation of the use of supercritical fluid extraction techniques to recover drugs from biological matrices
The use of supercritical fluid extraction (SFE) was evaluated for the determination of drugs of Forensic interest. Three matrices were investigated. The first two (blood and vitreous humor) were compared to SPE and LLE methodology currently in use at the Department of Forensic Science and Medicine. The third matrix, hair, was assessed to determine its usefulness as a marker of past drug use. Three types of drugs were investigated by SFE namely, Benzodiazepines, morphine and methadone. Successful methodology was developed for all three matrices and all three drug types, providing an efficient, reproducible alternative method to SPE and LLE, which reduced the environmental risks from organic solvents. The developed methods were applied to the analysis of authentic forensic samples. In addition to comparing well with the results obtained with the conventional techniques, good correlation was obtained between blood and vitreous humor results for temazepam, diazepam, methadone and morphine. Thus, in cases where a body is badly decomposed or burned, vitreous humor can be used as an alternative post-mortem sample. In addition to the determination of morphine, 6-monoacetyl morphine (6MAM) was used as marker of heroin abuse. 6MAM was detected in all three samples matrices, thus confirming the use of heroin prior to death. Hair analysis for all three types of drugs was carried out using a single extraction method. A wide range of concentrations was found for all drug types. As with blood and vitreous humor, 6MAM was detected and used as a marker of heroin abuse. From this, 61% of known heroin users were confirmed.