West Matthew J, Went Michael J
School of Physical Sciences, University of Kent, Canterbury, Kent, UK.
Spectrochim Acta A Mol Biomol Spectrosc. 2009 Jan;71(5):1984-8. doi: 10.1016/j.saa.2008.07.024. Epub 2008 Jul 26.
The application of powders to fingerprints has long been established as an effective and reliable method for developing latent fingerprints. Fingerprints developed in situ at a crime scene routinely undergo lifting with specialist tapes and are then stored in evidence bags to allow secure transit and also to preserve the chain of evidence. In a previous study we have shown that exogenous material within a fingerprint can be detected using Raman spectroscopy following development with powders and lifting with adhesive tapes. Other reports have detailed the use of Raman spectroscopy to the detection of drugs of abuse in latent fingerprints including cyanoacrylate-fumed fingerprints. This study involves the application of Raman spectroscopy for the analysis of drugs of abuse in latent fingerprints for fingerprints that had been treated with powders and also subsequently lifted with adhesive tapes. Samples of seized ecstasy, cocaine, ketamine and amphetamine were supplied by East Sussex Police and by the TICTAC unit at St. Georges Hospital Tooting. Contaminated fingerprints were deposited on clean glass slides. The application of aluminium or iron based powders to contaminated fingerprints did not interfere with the Raman spectra obtained for the contaminants. Contaminated fingerprints developed with powders and then lifted with lifting tapes were also examined. The combination of these two techniques did not interfere with the successful analysis. The lifting process was repeated using hinge lifters. As the hinge lifters exhibited strong Raman bands the spectroscopic analysis was more complex and an increase in the number of exposures to the detector allowed for improved clarification. Spectral subtraction was performed to remove peaks due to the hinge lifters using OMNIC software. Raman spectra of developed and lifted fingerprints recorded through evidence bags were obtained and it was found that the detection process was not compromised. Although the application of powders did not interfere with the detection process the time taken to locate the contaminant was increased due to the physical presence of more material within the fingerprint.
长期以来，粉末应用于指纹已被确立为一种有效且可靠的显现潜在指纹的方法。在犯罪现场原位显现的指纹通常会用专用胶带提取，然后存放在证据袋中，以便安全运输并保存证据链。在之前的一项研究中，我们已经表明，在用粉末显现并用胶带提取后，可以使用拉曼光谱法检测指纹中的外源物质。其他报告详细介绍了拉曼光谱法在检测潜在指纹中滥用药物方面的应用，包括经氰基丙烯酸酯熏蒸的指纹。本研究涉及应用拉曼光谱法分析经粉末处理并随后用胶带提取的潜在指纹中的滥用药物。查获的摇头丸、可卡因、氯胺酮和苯丙胺样本由东萨塞克斯郡警方和圣乔治医院图廷的TICTAC部门提供。将污染的指纹沉积在干净的载玻片上。在污染的指纹上应用铝基或铁基粉末不会干扰所获得的污染物拉曼光谱。还对用粉末显现然后用提取胶带提取的污染指纹进行了检查。这两种技术的结合并不妨碍成功分析。使用铰链式提取器重复提取过程。由于铰链式提取器显示出很强的拉曼谱带，光谱分析更加复杂，增加探测器的曝光次数有助于提高清晰度。使用OMNIC软件进行光谱减法以去除铰链式提取器产生的峰。获得了通过证据袋记录的显现和提取指纹的拉曼光谱，发现检测过程没有受到影响。尽管粉末的应用不会干扰检测过程，但由于指纹中存在更多物质，定位污染物所需的时间增加了。
