半导体纳米材料显现潜在手印技术的研究新进展

自纳米技术引入到法庭科学领域以来,因其独特的优势,拓宽了手印技术工作人员的思路,受到了国内外法庭科学家的青睐,成为当前国内外手印学科学家研究的热点。本文主要介绍了半导体纳米材料显现手印的概念特点,并就半导体纳米材料显现手印技术的发展历程和最新进展作了较为详细的归纳和总结。     

紫外激光技术显现潜在指印的研究

目的研究显现潜在指印的新技术。方法用自主研发的266nm短波紫外线输出的ND：YAG激光器作为激发光源激发渗透性客体表面的潜在指印,使指印发出荧光。结果能有效显现出亮纹线暗背景的潜在指印发光图像。结论利用该紫外激光技术可以显现纸张等渗透性客体表面的潜在指印。     

Novel O‐propyl,S‐propyl,and N‐propyl substituted 1,4‐naphthoquinones and 1,4‐anthraquinones as potential fingermark development reagents for porous surfaces

Lawsone is a 2‐substituted‐1,4‐naphthoquinone derivative, which has been proposed as an alternative to the reagents currently used for fingermark detection on porous surfaces. 2‐substituted‐anthraquinones, which contain an additional conjugated benzene ring, have a similar chemical structure to that of lawsone. In this study, a new series of 2‐substituted‐1,4‐naphthoquinones and 2‐substituted‐1,4‐anthraquinones were synthesized and completely characterized by¹H NMR,¹³C NMR, IR, and HPLC‐TOF/MS analyses. All newly synthesized 2‐substituted‐1,4‐quinones were investigated for their ability to develop latent fingermarks on porous surfaces, and this ability was compared with that of lawsone. Each fingermark developed was graded using an established method; thus, quantitative data were attributed to each fingermark. It has been demonstrated that the 1,4 ‐ quinones react with amino acids present in latent fingermarks on selected paper surfaces to produce faint yellow‐orange impressions, which exhibit strong photoluminescence when illuminated with a forensic light source at 440 nm and observed through a red filter. None of the compounds caused background darkening. The results obtained were generally similar to those of lawsone, however, 8‐dibromo‐2‐(propylamino)naphthalene‐1,4‐dione and 5,8‐dibromo‐2‐(propylthio)naphthalene‐1,4‐dione yielded better results for copier paper and colored (blue) copier paper used in this analysis. To the best of our knowledge, this is the first study to examine the role of 1,4‐anthraquinone derivatives as potential fingermark development reagents. The results indicate that 1,4‐quinones have a potential to be used as reagents for enhancement of latent fingermarks.     

Photoluminescence of blood by acidic hydrogen peroxide—A preliminary test

In this study, the authors found that treating blood with 1 M HCl and 2% (w/v) 5-sulfosalicylic acid (SSA) in 1% (v/v) hydrogen peroxide mixture can produce photoluminescence of blood. SSA was added as a blood fixer. The photoluminescence was induced by irradiation of a forensic light source at 505 nm, which was detected using a 550 nm barrier filter. In this experiment, various level of acid and hydrogen peroxide were tested to find the optimal formulation of reagents, spot tests were conducted with diluted blood to test the sensitivity of this reagent, and impressions in blood left on porous/nonporous surfaces were enhanced. The sensitivity of this solution was slightly lower than Bluestar and was similar to leucocrystal violet or leucomalachite green on both porous/non-porous surfaces. The photoluminescence of blood treated with this reagent has been observed over 2 months. Using this reagent, it was possible to observe fingermarks or footwear impressions in blood on a black porous/non-porous surface. Through this, it was found that using this reagent could enhance bloodstains regardless of the porosity or color of the surface.