纳米二氧化钛屏蔽紫外光法显现手印研究

A Study of Developing Fingermarks by Nano-Titanium Dioxide Shielding Ultraviolet-Ray

鉴于彩色和强荧光客体上手印难以显现的实际,报道了利用屏蔽紫外光显现手印的新方法。金红石相纳米二氧化钛对紫外光有很强的屏蔽性能。实验用二氧化钛粒径约为30nm,多为球形,对波长小于400nm的光有强烈吸收。通过刷显或抖显的方法,使纹线吸附足量的纳米二氧化钛颗粒,而客体表面不吸附或少吸附。在365nm紫外光照下,纹线呈暗色调,背景则为亮色调,拍照得到反差明显的影像。与传统的"502"胶熏显-罗丹明6G(或BBD)染色增显法比较,纳米二氧化钛屏蔽紫外光法显出的手印纹线流畅,细节特征清晰。研究表明:该法可以有效显现彩色或强荧光客体上手印,对于非渗透性客体上的陈旧手印也有比较理想的显现效果。该法具有简便、有效、快速和经济的特点,具有广阔的应用前景。

In view of the difficulty in developing fingermarks on the color or strong fluorescence surface,the present paper reported a novel method to develop fingermark by shielding ultraviolet-ray.Nano-titanium dioxide with rutile phase had extremely high shielding ability of ultraviolet-ray.The TEM indicatedthat the average particle size of rutile titanium dioxide in experiment was about 30 nm,and they were mostly sphericity.The UV-Vis spectra indicatedthat the rutile nanoparticles shield UV with wavelength less than 400 nm.The rutile nanoparticles were physically adsorbed on the ridges of fingermarks on the color or strong fluorescence surface adequately and were not or a little adsorbed on the object surface by dusting or shaking.The ridges of the developed fingermarks were dark and the background was light under irradiation of 365 nm.We could obtain good images,and the contrast of lightness between the ridge and the background was obvious.In contrast to traditional developing technique-superglue fuming-Rhodamine 6G （or BBD） dyeing strengthening technique,the effect of nano-titanium dioxide shielding ultraviolet-ray detection technique was better.By the new detection technique,the ridges of the developed fingermarks were smooth and the detail characteristics of the developed fingermarkes were clear.The research results indicatethat the nano-titanium dioxide particle is an effective and convenient developer of fingermark on the color or strong-fluorescence or color-strong fluorescence surface under irradiation of 365 nm with its shielding ultraviolet-ray property.Especially,the developer also has quite satisfactory effect on old fingermarks on the non-porous objects in contrast to traditional methods.The new detection technique is convenient,efficient,fast,and economical and has a wide application foreground in the field of fingermark developing.