茚二酮对疑难客体上汗潜手印的显现

Indanedione-zinc to Develop the Sweat Latent Fingerprints on Diffi cult-to-handle Objects

目的探究茚二酮试剂显现疑难客体上汗潜手印的可行性,以及对后期DNA提取检测的影响。方法先在A4纸上制作样本,用配制好的茚二酮试剂和茚二酮加锌试剂喷施在客体表面进行实验比对,选择茚二酮最佳显现试剂;然后在不同疑难客体上制作样本并放置不同时间后,用配制好的茚二酮加锌试剂喷施在客体表面进行显现操作,观察效果,拍照记录,统计分析;最后在牛皮纸和皮革上制作的实验组和对照组样本上提取DNA进行检测对比。结果茚二酮锌化试剂显现效果更佳,可以在不加热的条件下显现疑难客体上的汗潜手印,显现牛皮纸和砖头上的汗潜手印所需时间短,显出手印纹线清晰,细节特征点稳定,手印鉴定价值高;显现织物和皮革上的汗潜手印所需时间较长,显出手印纹线不太清晰,手印鉴定价值较小,但能显出手指印痕。汗潜手印用茚二酮锌化试剂显现后,对后期的DNA提取检测影响较小。结论采用茚二酮锌化试剂显现疑难客体上汗潜手印的方法具有可行性,其显出的手印纹线可进行手印鉴定,快速认定或排除嫌疑人;显出的手指印痕能精准定位接触痕迹,提高接触DNA检验的成功率。该方法有效衔接了手印检验和接触DNA检验两个检验过程,可应用于实际案件中。

Objective To probe into the feasibility of 1,2-indanedione-zinc agent to develop the sweat latent fingerprints on difficult-to-handle objects,and the potential influence of such a treatment on the following DNA detection.Methods The 1,2-indanedione and its zinc-added reagents were respectively sprayed onto the pre-grouped white A4-formatting paper(harboring the sweat latent fingerprints)that was afterwards not subjected to the conventional heating for the purpose to choose the treatment appropriate for both the fingerprint development and DNA detection.Through the fingerprint samples made onto several difficult-to-handle objects and placed for a period of time,the 1,2-indanedione-zinc reagent was adopted to develop the fingerprints with no heating so that the developing effects were observed and photos taken to have the results evaluated.Finally,DNA was comparably detected from the experimental/control samples on both the kraft paper and leather.Results 1,2-indanedione-zinc reagent was more effective,capable of developing the sweat latent fingerprints on a variety of difficultto-handle objects with no requirement of heating.The sweat latent fingerprint on either the kraft paper or brick was developed quickly,having the developed ridge details clearly observed and sharp contrast exposed,thereby demonstrating high value for fingerprint identification.Whereas longer time was required to develop the sweat latent fingerprints on both fabric and leather,yet the developed ridge details still being not clear enough for fingerprint identification,nonetheless the place being indicated of underdeveloped fingerprint showed the exact site for DNA to subsequently extract and detect.The 1,2-indanedione-zinc reagent exhibited little effect on the following DNA detection.Conclusions It is highly feasible to use 1,2-indanedione-zinc reagent to develop sweat latent fingerprints on varieties of difficult-to-handle objects.Meanwhile,the fingerprints,whether developed or not,can even locate the trace biological evidence precisely,thereby improving the successful probability of DNA genotyping.