利用茚三酮或DFO加强显现热敏纸张上的潜在指纹

本文介绍一种新技术——利用茚三酮或DFO加强显现热敏纸张上的潜在指纹。大部分热敏纸张的热敏剂表面,使用DFO或茚三酮石油醚溶液(NPB)显影时将会变黑。显现的指纹和背景之间反差很小。新技术介绍了在指纹和热敏层之间,用丙酮水洗,可以去掉黑色污斑。其它新的化学试剂漂洗,显现的指纹有清晰的纹线和很高的反差。大量使用这种技术,可以使试剂优化,成本降低,短时间内能处理大量检材。工作试剂包括商用、不挥发、含氮的有机化合物,也使用象NPB这样的浸透性试剂。

Enhancement of Ninhydrin or DFO-Treated Latent Fingerprints on Thermal Paper

A new method for enhancement of ninhydrin or 1,8-diazafluren-9-one(DFO)-treated latent finger- prints on thermal paper will be described.Most thermosensitive surfaces of thermal paper become dark when treated with DFO Or ninhydrin petroleum ether(NPB)solution.This effect minimizes contrast between the developed fingerprints and the background.The new method described reduces this dark staining without removing the thermosensitive layer and parts of the developed fingerprints,as occur with acetone wishing.Through the new method,the developed fingerprints appear in sharp lines and contrast.Extensive tests were performed,leading to an optimized working solution,which charges the paper with a minimum of chemicals,is cheap,and enables a large quantity of papers to be treated in short time.The working solu- tion contains commercially available,nonvolatile,nitrogenous organic compounds and can be used like the application of NPB solution by dipping.