Jones B J, Reynolds A J, Richardson M, Sears V G
Experimental Techniques Centre, Brunel University, Kingston Lane, Uxbridge, Middlesex, UB8 3PH, UK.
Sci Justice. 2010 Sep;50(3):150-5. doi: 10.1016/j.scijus.2009.08.001. Epub 2009 Sep 13.
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 TiO(2) 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.
基于二氧化钛的粉末常用于在深色表面上显影潜在指纹。对于分析胶带上的指纹，二氧化钛可悬浮在表面活性剂中，并以粉末悬浮液的形式使用。市售产品虽然名义上成分相似，但在指纹显影的有效性方面表现出不同程度的差异，有些粉末会附着在背景以及指纹上。对指纹粉末进行的X射线荧光分析（XRF）、分析型透射电子显微镜（TEM）、X射线光电子能谱（XPS）和激光粒度分析表明，TiO₂颗粒周围有一层数十纳米厚的涂层，该涂层由富含铝和硅的材料组成，并含有微量的钠和硫。这种铝硅酸盐通常用作抗结块剂，并有助于某些指纹粉末的附着力或功能；然而，铝硅酸盐的形态、厚度、覆盖率和组成是白色粉末配方之间的主要差异，可能与指纹显影效果的变化有关。
