Polymers on the crime scene: How can analytical chemistry help to exploit the information from these mute witnesses?

Abstract

Polymers are ubiquitous in everyday life, so it is very likely that they may be encountered on a crime scene as well. In order to exploit to the fullest extent the amount of information that these items contain, it is necessary to properly characterise them. The state of the art and the most recent advances in the forensic characterisation of polymeric items are presented. The qualitative and quantitative determination of the formulation is discussed, along with more innovative approaches, that focus on the features directly related to the macromolecular nature of such traces (molecular weight, degree of crystallinity, presence of comonomers, etc.)

Micro-Raman and Micro-FT-IR Spectroscopic Investigation of Raw and Dyed Pan Fibers

“…1 With the introduction of the microscopes in the spectroscopic techniques, such as micro-Raman and microinfrared (µ-Raman and µ-IR from now on) spectroscopy, the characterization of fibers, both raw and dyed, became an important aspect of their application. The characterization of polymer-based fibers is important for forensic, industrial and other purposes.…”

“…The characterization of polymer-based fibers is important for forensic, industrial and other purposes. [1][2][3][4][5][6][7] Raman and IR spectroscopic studies on fibers and dyed fibers showed that Raman data provided information about the dyes used in dyeing the fibers, but gave little information about the polymer, while IR spectra were found to be well suited for characterization of the polymer, but gave poor information on the dyes. 8 Some Raman experiments on dyed fibers have shown that this technique enables identification of the main dye present in colored fiber, but the components of the dyes are much more difficult to detect 9,10 because of their low overall content.…”

Forensic comparison of synthetic fibers

“…[100] Recent advances in the forensic characterization of polymeric items were reviewed, but they do not mention much about the GPC analysis of polymeric fibers. [2] As of today, there is no suitable forensic comparison analysis of fibers or plastics. However, GPC provides promising potential as a practical method for forensic fiber comparison even, with 1 μg sample sizes.…”

“…The transfer of trace material can link suspects, victims, and crime scenes by indicating contact of specific individuals with objects. [1,2] Many polymeric objects surround us in our daily lives, so there is a possibility that some of these polymers may be found at a crime scene. Fibers are one example, [2] as they can constitute some of the most important classes of forensic trace evidence, which often provide valuable information in a crime scene.…”

Ultraviolet-visible spectroscopic characterisation of automotive window tints for forensic purposes

“…[1][2][3][4] One form of potential trace evidence from such incidents is automotive window tint. This is a coating designed to reduce the glare from the sun to the observer within the vehicle and to protect the interior of cars from sun damage.…”