Dilag Jessirie, Kobus Hilton, Ellis Amanda V
Flinders University, School of Chemistry, Physics, and Earth Sciences, GPO Box 2100, Adelaide, SA 5001, Australia.
Forensic Sci Int. 2009 May 30;187(1-3):97-102. doi: 10.1016/j.forsciint.2009.03.006. Epub 2009 Apr 8.
The detection of latent fingermarks is a challenging task in forensic science. Here we present work using highly photoluminescent cadmium sulfide (CdS) quantum dots (QDs) encapsulated in an inexpensive biopolymeric chitosan matrix for latent fingermark detection. Cadmium ions were chelated within the chitosan matrix followed by the rapid addition of sodium sulfide to produce a CdS/chitosan nanocomposite. The average QD size was investigated as a function of precursor concentrations using ultra-violet-vis (UV-vis) spectrophotometry and the QDs were imaged with transmission electron microscopy (TEM). Fluorescence spectrophotometry of the QDs at an excitation of 450 nm showed a narrow emission at 531 nm and broad emission between 600 and 850 nm with a maximum at 716 nm. Freshly deposited latent fingermarks deposited on aluminium foil were clearly detected under a Rofin Polilight at 450 nm by dusting with a freeze-dried suspension of the CdS/chitosan nanocomposite and a surfactant, tergitol, giving a so-called quantum dot surfactant (QDS) powder.
在法医学中，检测潜在指纹是一项具有挑战性的任务。在此，我们展示了一项利用封装在廉价生物聚合物壳聚糖基质中的高发光硫化镉（CdS）量子点（QDs）进行潜在指纹检测的工作。镉离子在壳聚糖基质中螯合，随后快速加入硫化钠以制备CdS/壳聚糖纳米复合材料。使用紫外可见（UV-vis）分光光度法研究了平均量子点尺寸与前驱体浓度的函数关系，并用透射电子显微镜（TEM）对量子点进行成像。在450nm激发下对量子点进行荧光分光光度法检测，结果显示在531nm处有窄发射峰，在600至850nm之间有宽发射峰，最大发射峰在716nm处。通过用CdS/壳聚糖纳米复合材料和表面活性剂tergitol的冻干悬浮液进行撒粉处理，得到一种所谓的量子点表面活性剂（QDS）粉末，在450nm的Rofin Polilight灯下能够清晰检测出沉积在铝箔上的新鲜潜在指纹。
