目的 考察京尼平溶液显现手印的灵敏度,并探索DFO→京尼平→茚三酮方法联用显现纸张上潜在手印的效果。方法 通过使用京尼平溶液对同一手印样本进行一次、两次和三次浸泡处理,考察浸泡次数是否会影响显现效果;通过对京尼平→茚三酮、茚三酮→京尼平,京尼平→DFO和DFO→京尼平方法的组合设计方案与每种方法的单独使用进行比较研究,考察序列显现方法对显出手印的影响。结果 单用京尼平溶液对同一样本进行多次浸泡在自然光和荧光模式下都不会明显增强手印的显现效果,DFO方法先于京尼平、京尼平先于茚三酮使用都能起到增强手印纹线的效果。结论 京尼平方法显现手印灵敏度较高,DFO→京尼平→茚三酮方法联用可以进一步提高手印的显出率。

Objective Genipin, an extract from gardenia fruit, can react with amino acid in the fingerprint deposits, making it a fingerprint developing agent. Latent fingerprints on paper developed with genipin shown blue under white light but red fluorescence under an alternative light source. This method is safe and environment-friendly by use of this natural product. Nowadays, there are a variety of methods chosen to develop latent fingerprints on porous surface, for example, those of using ninhydrin, DFO, IND, PD and ORO. Presently, forensic scientists pay more attention to the combination of these methods. Therefore, how to find the good association of these methods to enhance the number and effect of developed fingerprints appears to be a trend in fingerprint technology research. This paper investigated the sensitivity of genipin agent and explores the correlation of using genipin, ninhydrin and DFO, and finally sets up a sequential procedure which can apparently elevate the effect of developed prints on paper surface.Methods Natural fingerprints ranging from strong to weak (‘depletion’ prints), taken from ten donors, were deposited on strips of copy paper, newspaper, kraft and offset paper. We used “split print” approach by evenly cutting the fingerprint into two parts. Firstly, in order to evaluate whether the soak time could influence the result, we immersed the same sample in genipin solution for one, two and three times respectively and observed the effect under white light and alternative light source respectively. Secondly, as DFO should be used before ninhydrin, we designed four procedures by using genipin prior to ninhydrin and comparing with single use of genipin, ninhydrin prior to genipin and comparing with single use of ninhydrin, genipin prior to DFO and comparing with single use of DFO, and finally DFO prior to genipin and comparing with single use of genipin. Each experiment was conducted separately, and the result was observed both under white light and fluorescence.Results It failed to enhance the fingerprint developing effect when samples were treated with different times of single use of genipin either under white light or fluorescence, but the addition of DFO prior to genipin or genipin prior to ninhydrin presented better effect than single use of one agent although none of better results were obtained with using genipin prior to DFO or ninhydrin prior to genipin.Conclusions The method of sequential addition of DFO next genipin and final ninhydrin is more efficient with enhancing the effect of the developed fingerprints while genipin is sensitive enough to develop fingerprints with sample-treating only once.