荧光黄湿粉显现手印方法的初步研究

目的研发一种具有荧光特性的黄湿粉,以提取遗留在不同客体上的不同种类的手印。方法在100mL温水中加入适量的表面活性剂,溶解后加入100g荧光黄颜料,选用不同种类客体及不同种类物质手印进行显现实验,比较显现效果;结果遗留在光滑非渗透性客体及半渗透性客体表面的汗潜、油潜手印,显出的手印纹线流畅、反差强、荧光强;结论荧光黄湿粉可适用于光滑非渗透性客体及半渗透性客体表面新鲜或较新鲜汗潜手印、油潜手印及血潜手印的显现。     

真空镀膜中膜系选择对潜手印显现的影响

目的探究在真空镀膜中不同镀膜材料能否显现出潜手印并比较不同镀膜金属显现手印的效果。方法使用不同的镀膜金属显现多种类型客体表面的潜手印。结果存在可替换镀膜材料。结论可替换镀膜金属对潜手印显现的效果良好,纹线清晰连贯,背景反差大,并对特定客体上的手印显现极具优势。     

群青悬浮液显现手印的研究

目的确定群青小颗粒悬浮液显现手印的最佳配方及适用范围;方法配置群青小颗粒悬浮液的不同浓度,对不同种类手印、不同时间手印以及不同客体上的手印进行试验显现;结果以1‰的1227表面活性剂水溶液为分散剂、浓度为20%的群青悬浮液为最佳配方;结论本研究结果可用于光滑非渗透性客体上遗留时间较短的多种物质手印的显现。     

利用CdSe巯基乙酸溶液显现水浸客体表面潜手印

目的研究水浸客体表面潜指纹的显现方法;方法利用CdSe巯基乙酸溶液显现被水浸泡过的黄色封箱胶带、黑色塑料袋、玻璃等常见非渗透性客体上的潜手印,讨论影响水浸非渗透性客体上潜手印显现效果的各种因素,并与传统方法进行比较,初步探讨了CdSe巯基乙酸溶液显现水浸非渗透性客体表面潜手印的方法;结果使用巯基乙酸包覆CdSe纳米复合材料显现潜在手印,使每分子纳米复合材料外表包覆足够数量的羧基,则可以提高它同手印残留物的结合能力,从而得到更高清晰度、更高分辨率的手印显像;结论巯基乙酸包覆CdSe纳米复合材料可以很好的显现水浸塑料、胶带等表面潜指纹。     

新型亲油性纳米二氧化硅粉末在手印显现中的应用

目的 比较新型亲油性纳米二氧化硅粉末显现手印的效果.方法 应用亲油性纳米二氧化硅粉末与现场勘查箱内金粉、银粉和黑色磁性粉显现非渗透性客体表面油汗混合手印,并在自然光下观察比较显现效果.结果 亲油性纳米二氧化硅粉末显现出的手印图像纹线清晰连贯,背景反差好.结论 亲油性纳米二氧化硅粉末显现手印具有一定的优势.     

开拓汗潜手印显现的新领域

系统论述了JHF-系列荧光粉末和JHC-系列荧光磁性粉显现汗液指纹的理论基础和主要特点,比较了与金属粉末显现手印的不同效果,列举了在不同客体和不同留痕条件下显现的汗潜手印的方法.     

二氧化钛显现手印研究

目的建立应用二氧化钛的小微粒悬浮液来显现潜在手印的方法。方法选择6种不同客体,分别取普通汗和皮脂汗手印各40枚,各保存1天和7天,用二氧化钛小微粒悬浮液进行手印显现。结果保存1天和7天的汗潜手印显现结果没有很大区别,但皮脂汗手印显现效果好于普通汗手印。结论二氧化钛的小微粒悬浮液可以有效地显现出光滑非渗透性客体表面的潜手印。     

纳米粉末显现水果和蔬菜表面手印

目的研究纳米粉末显现水果和蔬菜表面的手印。方法纳米Fe3O4粉末的显现方法同常规磁性粉末;纳米ZnO粉末则是撒粉于可疑表面,然后用吸耳球轻轻吹掉多余的粉末直到手印显出,利用多波段光源,在紫外一可见光范围内拍照;并与松花粉显现法比较。结果纳米Fe3O4粉末可以清晰显现4种检材表面的手印;纳米ZnO粉末可显现除土豆之外的3种检材表面的手印,尤其显现西红柿表面手印的效果最好;与松花粉相比,纳米粉末显现的手印纹线流畅、细腻,细节特征清晰。结论利用纳米粉末可以有效显现水果蔬菜表面的手印,显出的纹线在紫外－可见光范围内拍照均可以得到反差较大的影像。     

基于PolyCyano UV粉末显现手印的新技术

目的介绍1种新型PolyCyano UV粉末显现非渗透性光滑客体表面潜手印的新技术。方法选取多种常见客体,由志愿者在客体上捺印指印,将PolyCyano UV粉末加热至230℃使其升华,待该粉末在手印纹线上聚合后使用长波紫外线照射若干时间,然后在蓝光激发下使用滤色镜观察并拍照。结果绝大部分非渗透性光滑客体表面上的潜手印均有很好的显现效果,尤其是对浅色或白色客体有十分明显的荧光效果,对陈旧手印也有较好的显现效果。结论该方法熏显操作简便、显现时间短、无需二次染色增强、不破坏生物检材、显现效果明显,适合推广使用。     

高压静电法显现金属表面汗潜手印

目的建立一种加载高压静电法,提高金属表面手印显现效果。方法利用自行设计的静电加载设备,在常见金属客体表面分别遗留1、3、7、15d的手印,分别用静电加载和普通磁性粉进行显现。结果高压静电法显现金属表面汗潜指印效果均有明显的提高。结论该方法现场操作性强,简便有效。     

Evaluation of DNA Extraction Methods for Processing Fingerprint Powder-Coated Forensic Evidence

In unison, fingerprinting and DNA analysis have played a pivotal role in forensic investigations. Fingerprint powders that are available on the market can come in a range of colors and with specific properties. This study evaluated the efficiency of DNA extraction from samples coated with 3 brands of fingerprint powders: Lightning, Sirchie, and SupraNano, covering a range of colors and properties. A total of 23 fingerprint powders were tested using the Chelex, Promega DNA IQ™, and Applied Biosystems™ PrepFiler™ DNA extraction protocols. The DNA IQ™ and PrepFiler™ methods extracted higher yields of DNA in comparison to Chelex, which also accounted for better quality of PowerPlex x00AE; 21 DNA profiles recovered. There were no signs of degradation or inhibition in the quantification data, indicating that samples returning low DNA yield was due to interference during DNA extraction and not PCR inhibition. DNA profiles were recovered from the majority of fingerprint powders with only a single powder, Sirchie Magnetic Silver, failing to produce a profile using any of the methods tested. A link was observed between the DNA extraction chemistry, fingerprint powder property, that is, nonmagnetic, magnetic and aqueous, and the brand of fingerprint powder. Overall, the DNA IQ™ method was favorable for nonmagnetic fingerprint powders, while magnetic fingerprint powders produced more DNA profiles when extracted with the PrepFiler™ chemistry. This study highlights the importance of screening DNA extraction chemistries for the type of fingerprint powder used, as there is not a single DNA extraction method that suits all fingerprint powder brands and properties.     

胶带粘面手印荧光显现剂的研发与应用

目的根据胶带粘面上潜在手印的特点,利用染料和潜手印的理化性质,研究开发胶带粘面手印荧光显现剂。方法在各种胶带粘面上显现潜在手印,并与常规的碳素墨水染色法进行比较。结果在长波紫外线照射下手印呈黄色明亮荧光,手印纹线清晰、连贯,基本不受手印遗留时间、客体表面颜色和性质的影响。结论胶带粘面上的汗潜手印和血潜手印用荧光显现剂显现效果优于碳素墨水染色法,在实际案件的侦破中有较好的应用前景。     

TiO2纳米粉末显现潜在指纹研究

目的建立并比较了TiO2纳米粉末与常规粉末的显现效果。方法使用配粉、色素、疏水性物质对TiO2纳米粉末进行改性，并通过正交实验设计法对综合改性条件进行优化。结果与普通粉末相比，TiO2纳米粉末由于粒度上的优势，具有显现细节特征多、背景表面无粘粉、显现陈旧指纹能力强等优点；通过添加配粉、色素、疏水性物质等改性剂，可以增加TiO2纳米粉末的流散性、扩大粉末与客体背景的反差并提高了其显现潮湿客体的能力。最佳改性方案为使用20％的色素、5：2的配粉比例以及十六胺做疏水性物质。结论TiO2纳米粉末能更有效显现非渗透性客体表面上的潜指纹。     

Techniques for fingerprint recovery on vegetable and fruit surfaces used in Slovenia — A preliminary study

An examination was conducted to investigate whether certain dactyloscopic powders and reagents can recover latent fingerprints on vegetable and fruit surfaces (apple, banana, tomato and potato). Two fingerprint powders, Swedish Soot powder mixture (Swedish Black), Silver Special powder and cyanoacrylate fuming (CA), were investigated. The results have shown that detection with Swedish blackpowder is the most suitable procedure as the percentage finger marks which were of adequate quality for further examination, was higher than with any other technique examined.     

Fingerprint recovery from human skin surfaces.

A study was conducted to investigate whether certain dactyloscopic powders and reagents can recover latent fingerprints on human skin surfaces. Four fingerprint powders, Magnetic Jet Black, Magnetic Silver, Silver Special, Swedish Black, and two other methods, cyanoacrylate fuming (CA) and Ruthenium tetroxide (RTX), were used. Having examined skin surfaces with a forensic light source, we observed that the fingerprint impressions remained visible up to 15 min after intentionally placing them on the skin surface of living subjects and dead bodies. Finger marks were recovered and positive results were achieved with Magnetic Black and Swedish Black powder on living subjects. On dead bodies finger marks treated with cyanoacrylate were visible but those treated with RTX, Swedish Black and Magnetic Jet Black powder were useful for potential comparison. On dead bodies best results were obtained with RTX method.     

Nano-scale composition of commercial white powders for development of latent fingerprints on adhesives

Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide can be suspended in a surfactant and used in the form of a powder suspension. Commercially available products, whilst having nominally similar composition, show varying levels of effectiveness of print development, with some powders adhering to the background as well as the print.X-ray fluorescence (XRF), analytical transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and laser particle sizing of the fingerprint powders show TiO₂ particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material, with traces of sodium and sulphur. Such aluminosilicates are commonly used as anti-caking agents and to aid adhesion or functionality of some fingerprint powders; however, the morphology, thickness, coverage and composition of the aluminosilicates are the primary differences between the white powder formulations and could be related to variation in the efficacy of print development.     

DNA Profiles from Fingerprint Lifts—Enhancing the Evidential Value of Fingermarks Through Successful DNA Typing

This study evaluated the compatibility of the most common enhancement methods and lifting techniques with DNA profiling. Emphasis is placed on modern lifting techniques (i.e., gelatin lifters and Isomark?) and historical fingerprint lifts for which limited research has been previously conducted. A total of 180 fingerprints were deposited on a glass surface, enhanced, lifted, and processed for DNA typing. DNA could be extracted and profiled for all the powders and lifts tested and from both groomed fingerprints and natural prints with no significant difference in the percentage of profile recovered. DNA profiles could also be obtained from historical fingerprint lifts (79.2% of 72 lifts) with one or more alleles detected. These results demonstrate the compatibility between different powder/lift combinations and DNA profiling therefore augmenting the evidential value of fingerprints in forensic casework.     

小颗粒黄色荧光粉YAG：Ce,Gd表面氨基化修饰显现指印的研究

目的研究高效、环保的手印显现技术,拓展黄色荧光粉YAG：Ce,Gd的应用范围。方法采用液相沉积法对黄色荧光粉进行氨基化修饰,并对修饰前后粉体进行红外光谱、光学性能及表面形貌的分析。结果氨基化的黄色荧光粉能够成功地显现非渗透性和渗透性客体上的油脂手印和汗液手印。结论本方法使手印显现效果达到高效、无毒、无损的要求。     

Fluorescent TiO2 powders prepared using a new perylene diimide dye: applications in latent fingermark detection

A new, highly fluorescent dye was synthesised using oleylamine combined with a perylene dianhydride compound. The new dye was characterised by 1H NMR, UV-vis spectroscopy and fluorescence spectroscopy as well as quantum yield. The dye was absorbed onto titanium dioxide nanoparticles for use as a fingerprint detection powder. The new fluorescent powder was applied to latent fingermarks deposited onto different non-porous surfaces and compared with commercial fluorescent powders. The powder exhibits strong fluorescence at 650-700 nm under excitation at 505 nm. On glass surfaces, the new powder gave images showing tertiary-level detail of the fingermark ridges with almost no background development. Compared with current magnetic fluorescent powders, the new powder was slightly weaker in fluorescence intensity but produced significantly less background development, resulting in good contrast between the fingermark and the substrate.     

The spectroscopic detection of exogenous material in fingerprints after development with powders and recovery with adhesive lifters

The application of powders to fingerprints has long been established as an effective and reliable method for developing latent fingerprints. The powders adhere to the ridge pattern of the fingerprint only, thus allowing the image to be visualised. Fingerprints developed in situ at a crime scene routinely undergo lifting with specialist tapes to facilitate subsequent laboratory analysis. As with all recovered evidence these samples would be stored in evidence bags to allow secure transit from the scene to the laboratory and also to preserve the chain of evidence. In this paper, the application of Raman spectroscopy for the analysis of exogenous material in latent fingerprints is reported for contaminated fingerprints that had been treated with powders and also subsequently lifted with adhesive tapes. A selection of over the counter (OTC) analgesics were used as samples for the analysis and contaminated fingerprints were deposited on clean glass slides. The application of aluminium or iron based powders to contaminated fingerprints did not interfere with the Raman spectra obtained for the contaminants. In most cases background fluorescence attributed to the sebaceous content of the latent fingerprint was reduced by the application of the powder thus reducing spectral interference. Contaminated fingerprints developed with powders and then lifted with lifting tapes were also examined. The combination of these two techniques did not interfere with the successful analysis of exogenous contaminants by Raman spectroscopy. The lifting process was repeated using hinge lifters. As the hinge lifters exhibited strong Raman bands the spectroscopic analysis was more complex and an increase in the number of exposures to the detector allowed for improved clarification. Raman spectra of developed and lifted fingerprints recorded through evidence bags were obtained and it was found that the detection process was not compromised in any way. Although the application of powders did not interfere with the detection process the time taken to locate the contaminant was increased due to the physical presence of more material within the fingerprint. The presence of interfering Raman bands from lifting tapes is another potential complication. This, however, could be removed by spectral subtraction or by the choice of lifting tapes that have only weak Raman bands.