Detection of nitro-organic and peroxide explosives in latent fingermarks by DART- and SALDI-TOF-mass spectrometry.

The ability of two mass spectrometric methods, surface-assisted laser desorption/ionization-time of flight-mass spectrometry (SALDI-TOF-MS) and direct analysis in real time (DART-MS), to detect the presence of seven common explosives (six nitro-organic- and one peroxide-type) in spiked latent fingermarks has been examined. It was found that each explosive could be detected with nanogram sensitivity for marks resulting from direct finger contact with a glass probe by DART-MS or onto stainless steel target plates using SALDI-TOF-MS for marks pre-dusted with one type of commercial black magnetic powder. These explosives also could be detected in latent marks lifted from six common surfaces (paper, plastic bag, metal drinks can, wood laminate, adhesive tape and white ceramic tile) whereas no explosive could be detected in equivalent pre-dusted marks on the surface of a commercial lifting tape by the DART-MS method due to high background interference from the tape material.

Detection of drugs and their metabolites in dusted latent fingermarks by mass spectrometry.

A hydrophobic silica dusting agent containing carbon black has been used with latent finger marks to demonstrate that the agent can act as an enhancing matrix to generate a simple method for detecting a range of drugs using surface assisted laser desorption/ionisation time-of-flight mass spectrometry (SALDI-TOF-MS) in positive ion reflectron mode. The dusting agent produces developed marks for locating/visualising the prints whilst also acting as a SALDI-TOF-MS enhancer that is equivalent to the standard matrix enhancer 2,5-dihydroxybenzoic acid. This method has been applied to the analysis of latent fingermarks for contact residues on fingers, and for detection of illicit drugs for both parent drugs and their metabolites.