Application of Multi-Element Scanning Thermal Analysis (MESTA) Method in Tire Identification for Forensic Purposes

Chiou-Herr Yang ； Yuch-Ping Hsieh ； Yung-Fou Chen ； Wei-Lun Yan

《Forensic Science Journal》 18卷1期 (2019/12) Pp. 1-8

https://doi.org/10.6593/FSJ.201912_18(1).0001

摘要

Traffic accidents or criminal cases may lead car to leave tire samples or tire marks on an accident scene or a criminal scene. Tire samples left in a scene can be a valuable source of information that links an accident or criminal scene to the suspected vehicle. However, it is difficult to analyze a tire sample in detail for forensic purposes by chemical method or spectroscopic method due to its low solubility in solvents and dark color. The objective of this study was to explore the feasibility of using the multi-element scanning thermal analysis (MESTA) for tire samples identification in forensic science. In this study, 13 tire samples were collected randomly from various sources. Powder samples were scraped from tire surfaces by files. The scraped powder was analyzed by the MESTA method. The MESTA C, N and S thermograms in the three temperature regions, namely, 250-450 °C, 451-590 °C and 590-710 °C were chosen as the temperature interval for analysis. The result of statistical analysis shown that there is significant variations among the total C (carbon), N (nitrogen), S (sulfur) concentrations and peaks ratio to differentiate those tire samples. Totally, there are 12 parameters that can be used to distinguish one sample from others. Principal component analysis (PCA) and hierarchical clusters analysis (HCA) were performed for discriminating different tire samples. Results shown that the combination of MESTA and HCA can be a potential technique for distinguish tire samples that are from different sources.

關鍵字

tires ； rubber ； multi-element scanning thermal analysis (MESTA) ； forensic identification