新型碘铁手印显现方法的实践性研究

A Practical Study on a New Iodine-Iron-Based Handprint Detection Method

依据碘单质和金属铁在有水作催化剂条件下发生反应,放出大量的热,从而使多余的碘升华的原理,对司法实践中常见的几种客体上的新鲜汗潜手印进行显现固定。碘铁手印显现法具有以下优点:反应匀速进行;不会瞬间产生大量的碘蒸气而使熏显过度;显现的纹线清晰连贯。通过选择合适的配比,即当碘与铁物质的量的比为1∶1(碘为15.68 g、铁为3.46 g)时,加入0.40 mL蒸馏水时,获得了最佳显现效果。相比于传统加热碘熏法和碘锌手印显现法,碘铁手印显现法显现效果优、稳定性好,在常温下有些客体上显现的手印能够保存一周不褪色。该方法适用于司法实践中常见渗透性及非渗透性客体上汗潜手印的显现。

Iodine and metal iron react in the presence of water as catalyst,releasing a large amount of heat,so that the excess iodine sublimes.According to this principle,fresh latent sweat handprints on several common objects in judicial practices are developed and fixed.Iodine-iron-based handprint detection method has the following advantages:reaction at uniform speed,no over-cyanoacrylate fuming because of no vast amount of iodine vapor release instantly and clear and connected lines appearance.When the ratio of iodine to iron is 1∶1,namely iodine 15.68 g and iron 3.46 g,with 0.40 mL of distilled water added,the best development effect can be obtained.Compared with the traditional heating iodine fumigation method and iodine-zinc-based method,the iodine-iron-based method shows high sensitivity and stability.Furthermore,the developed handprints on some objects do not fade for a week at room temperature.In conclusion,this method is applicable to the development of sweat handprints on common permeable and non-permeable objects in judicial practices.