Elemental Analysis and Characterization of Electrical Tape Backings by LA-ICP-MS

• NCJ Number: 252635
• Journal: Forensic Chemistry Volume: 4 Dated: June 2017 Pages: 96-107
• Author(s): Claudia Martinez-Lopez; Tatiana Trejos; Andria H. Mehltretter; Jose R. Almirall
• Date Published: June 2017
• Length: 12 pages
• Grant Number(s): 2015-DN-BX-K050
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical); Report (Study/Research); Report (Grant Sponsored); Program/Project Description

Annotation

Since adhesive tapes are commonly found as physical evidence in cases involving violent crimes and national security threats, this research evaluated the utility of Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) for the characterization of chemical signatures of electrical tapes for forensic comparison and provenance purposes.

Abstract

The backings of 90 black electrical tapes, previously characterized by microscopical examination, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), Fourier Transform Infrared Spectroscopy (FTIR) and Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS), were analyzed by LA-ICP-MS to evaluate the ability of the technique to discriminate samples originating from different sources and to associate pieces of tapes originating from the same roll. The results showed that LA-ICP-MS is a useful tool that complements current protocols for the organic and inorganic characterization and comparison of electrical tapes and results in improved discrimination and superior characterization. The developed LA-ICP-MS method alone provided 94 percent correct discrimination of the tapes known to originate from different rolls and 100 percent correct association of the tapes known to originate from the same roll. Moreover, LA-ICP-MS captured a large amount of compositional information, as the use of elemental profiles alone provide similar discrimination and classification capabilities as all the conventional methods together. The analytical sensitivity of LA-ICP-MS provides a means for the classification of tapes to support investigations as well as the potential for database searching capabilities in the future. (Publisher abstract modified)