Hydrophobic silica nanopowder has been used as an effective latent fingermark development agent and subsequently as an enhancement agent in the surface-assisted laser desorption/ionisation-time of flight (SALDI-TOF) mass spectrometry for analysis of fingermark components. The technique has been used in the detection of nicotine and cotinine in the fingermarks of smokers. In order to have confidence in concluding that the nicotine in such samples is indicative of cigarette usage, it is necessary to establish that contamination by environmental contact or from hand to hand contact with smokers or from passive smoking does not lead to false identification of non-smokers as smokers. To investigate this possibility, the background level of nicotine in fingermark material from a number of commonly used places was determined. In addition, a series of experiments was carried out to assess the extent to which nicotine can be transferred through handshakes and finger transfer as well as touching of door handles. The rate of loss of nicotine from latent fingermarks was also assessed over a 24-h period under ambient laboratory conditions. Finally, a laboratory-based model system was evaluated to ascertain the possible transport of nicotine in cigarette smoke from a source to adjacent areas to simulate cross-contamination of a non-smoker by passive exposure. It was observed that person-to-person transfer from a smoker to a non-smoker can occur following handshakes but at low levels and that passive cross-contamination from contact with surfaces is possible under simulated conditions. However, levels of nicotine in the wider environment were found to be too low for detection using this technique which may reflect the half-life of nicotine in latent fingermarks which was about 11h. Likewise, transfer via smoke is possible to objects within about 0.1m of the cigarette but it is unlikely that significant secondary nicotine contamination will occur on the faces and hands of adjacent non-smokers.
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