Bowen Andrew, Stoney David
Stoney Forensic, Inc., 14101 Willard Road, Suite G, Chantilly, VA 20151, USA.
J Forensic Sci. 2013 May;58(3):789-96. doi: 10.1111/1556-4029.12071. Epub 2013 Mar 12.
Fibers are a commonly encountered evidence type and fiber comparisons are routinely conducted. When the characteristics of questioned and known fibers correspond, the probative value is limited because the characteristics compared are determined by their manufacture. It would be valuable to test the hypothesis that questioned fibers originated from a specific carpet. One means of testing this is to analyze fine particles on the fibers. A procedure was developed for removing adhering particles from fibers and preparing them for scanning electron microscopy/ energy dispersive X-ray spectrometry (SEM/EDS) analysis. The efficacy of several fluids (acetone, ethanol, hexanes, aqueous ethanol, aqueous sodium hexametaphosphate) and agitation methods (sonication and vortexing) for removing particles from fibers was evaluated. The most effective method evaluated was sonication in ethanol for 10 min. The recovered particles were filtered onto a polycarbonate filter and analyzed by automated SEM/EDS analysis to generate data on the particle assemblage. This method makes possible future research to test the within-item and between-item variability of particle assemblages on fibers.
纤维是一种常见的证据类型，纤维比对工作也经常开展。当可疑纤维与已知纤维的特征相符时，其证明价值有限，因为所比较的特征是由其生产制造过程决定的。检验可疑纤维是否源自特定地毯这一假设具有重要意义。检验此假设的一种方法是分析纤维上的微小颗粒。已开发出一种从纤维上去除附着颗粒并为扫描电子显微镜/能量色散X射线光谱仪（SEM/EDS）分析做准备的程序。评估了几种液体（丙酮、乙醇、己烷、乙醇水溶液、六偏磷酸钠水溶液）和搅拌方法（超声处理和涡旋）从纤维上去除颗粒的效果。评估出的最有效方法是在乙醇中进行10分钟的超声处理。将回收的颗粒过滤到聚碳酸酯滤膜上，并通过自动SEM/EDS分析进行分析，以生成关于颗粒组合的数据。该方法使未来测试纤维上颗粒组合的项目内和项目间变异性的研究成为可能。
