Nanofrontier Pte Ltd., Research TechnoPlaza, 50 Nanyang Drive, Singapore 637553, Singapore.
Forensic Sci Int. 2010 Jul 15;200(1-3):28-34. doi: 10.1016/j.forsciint.2010.03.022. Epub 2010 Apr 14.
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.
疏水性二氧化硅纳米粉末已被用作一种有效的潜伏指纹显现剂，并随后作为增强剂用于表面辅助激光解吸/电离-飞行时间（SALDI-TOF）质谱分析指纹成分。该技术已用于检测吸烟者指纹中的尼古丁和可替宁。为了有信心得出结论，即此类样品中的尼古丁表明吸烟，有必要确定环境接触或与吸烟者手对手接触或被动吸烟不会导致将非吸烟者错误地识别为吸烟者。为了研究这种可能性，确定了从许多常用场所获得的指纹材料中尼古丁的背景水平。此外，进行了一系列实验以评估尼古丁通过握手、手指转移以及触摸门把手转移的程度。还评估了在环境实验室条件下 24 小时内潜伏指纹中尼古丁的损失率。最后，评估了基于实验室的模型系统，以确定在源到相邻区域的模拟被动暴露中，香烟烟雾中的尼古丁可能发生的运输情况，以模拟非吸烟者的交叉污染。观察到，吸烟者与非吸烟者之间可以通过握手进行人与人之间的转移，但水平较低，并且在模拟条件下，接触表面可能会发生被动交叉污染。但是，在更广泛的环境中发现尼古丁水平太低，无法使用该技术进行检测，这可能反映了潜伏指纹中尼古丁的半衰期约为 11 小时。同样，通过烟雾向香烟 0.1 米范围内的物体转移是可能的，但香烟附近的非吸烟者的面部和手部不太可能发生明显的二次尼古丁污染。
