Drugs detection in fingerprints

Fingerprints left at a crime scene are used to connect the crime to a person who may have been present there. Fingerprints can also be used as alternative material in forensic toxicology. The detection of drugs in fingerprint samples can be used to show that an individual touching an item has consumed specific drugs. The aim of this study was to check the usefulness of fingerprints in drug analyses and detection of some analytes in this material. Fingerprint samples were collected on glass slides from a volunteer who consumed separately tablets containing pseudoephedrine, codeine, dextromethorphan, and used lidocaine spray. Moreover, fingerprints of individuals receiving sertraline, hydroxyzine and trazodone as part of their long-term treatment were analysed. The detection of drugs was conducted using the liquid chromatography tandem mass spectrometry (LC-MS/MS) technique. After administration of single doses of drugs, they were detected up to 36 h (pseudoephedrine), 24 h (codeine), and less than 6 h (dextromethorphan and lidocaine) with maximum concentrations observed at 1-4 h. In fingerprints of a person who has finished treatment with hydroxyzine and sertraline it was possible to detect these drugs even 20 days after last drug administration. Cetirizine (hydroxyzine metabolite) and mCPP (trazodone metabolite) were determined in fingerprints of individuals under long-term treatment. This work has demonstrated that forensic toxicology can use fingerprints as alternative material. Drugs can be detected in fingerprints even after their single doses. Parent compounds predominate over metabolites in the fingerprints. The detection window depends on the type of drug and duration of the treatment.