Dentin for forensic drug monitoring
- Published: Dec 21, 2014
- Author: Steve Down
- Channels: Base Peak
Drugs of abuse can be detected in dentin, providing a novel matrix for forensic toxicology studies. This approach has been examined on a few occasions previously but the new report from scientists in Germany and Switzerland emphasised the fact that dental pulp was removed before analysis, thereby eliminating interferences from blood inside the pulp.
There are two ways in which substances in the mouth can enter dental tissue: via the blood vessels or via the enamel or exposed dentin. The enamel/dentin route is possible because of the pH changes in the mouth caused by the acidic compounds that are present. The acids eat away enamel and dentin but, when the acids are removed, the pH increases again so that remineralisation can occur with the help of saliva. During remineralisation, other compounds present in the mouth like pigments from foods and tobacco, and drugs, become incorporated.
The new approach, described in Journal of Mass Spectrometry, ensures that all of the pulp tissue was removed before the drugs were analysed by liquid chromatography/mass spectrometry. For a series of artificially loaded dentin samples, amphetamine, methamphetamine, MDMA, MDEA, codeine, cocaine, benzoylecgonine and morphine were measured at 20-80 pg/mg.
The method will be useful in post-mortem cases where there is limited tissue available for analysis, helped by the long-term preservation of drugs in teeth. For instance, morphine can be detected in teeth of heroin addicts two years after death.