Practical colorant identification applied to forensic casework
Palenik, C.S. (2013) “Practical colorant identification applied to forensic casework” in session Analytical Chemistry as Detection: Case Studies in Forensic Science. SCIX 2013 (Milwaukee, WI).
Presented on: 10/1/2013
Forensic microscopy and trace evidence analysis are usually conducted by means of comparative examinations: for example, hair comparisons, fiber comparisons, paint comparisons, glass comparisons, etc. While this is a necessary and pragmatic approach, the full extent of information that microscopical analysis can provide is often overlooked, particularly in an era of certifications and accreditations, where SOPs tend to discourage thoughtful and creative analytical approaches to problem solving. For example, many laboratories that operate under such constraints will not even open a package of evidence unless a potential source (i.e., comparison sample) is submitted in parallel.
While the analysis of samples without comparative material can be more time consuming and requires a greater understanding of the material being studied, a great deal of factual and investigative information can be elucidated from such samples by applying the scientific approach in a thoughtful manner. While there are many types of evidence that can be exploited through such investigative (as opposed to comparative) study, this talk will focus specifically on the types of investigative information that can be obtained through the characterization of colorants (dyes and pigments) and their surrounding media, be they paint, food, cosmetics, art, or even an industrial tool. Through the presentation of casework based examples that represents the cutting edge of practical colorant analysis and identification through microscopy, spectroscopy, and microchemistry, this talk will illustrate the types of information that can be obtained from a ubiquitous, but generally overlooked component of trace evidence: the colorant.