Date of Award

1-1-2021

Language

English

Document Type

Master's Thesis

Degree Name

Master of Science (MS)

College/School/Department

Department of Chemistry

Content Description

1 online resource (v. 24 pages) : color illustrations.

Dissertation/Thesis Chair

Igor K Lednev

Committee Members

Mehmet Yigit

Keywords

Body Fluids, Chemometrics, False Positives, Raman Spectroscopy, Substrate Interference, Blood, Body fluids, Raman spectroscopy, Chemistry, Forensic, Multivariate analysis

Subject Categories

Analytical Chemistry

Abstract

Body fluids, such as blood and semen, can provide invaluable information to a criminal investigation. As such, it is imperative that body fluid evidence is properly detected and identified. Our laboratory has developed a methodology to universally detect and identify body fluids using Raman spectroscopy and chemometrics. This methodology was developed under ideal conditions, which are rare in the field. Body fluid evidence can be found on substrates that produce a large Raman signal that can hinder detection of body fluid traces, which produce a weak signal. This project proposes the use of a statistical program called HAMAND (Hypothetical Addition Multivariate Analysis with Numerical Differentiation) as a solution to this problem. The software uses a reference spectrum of the target analyte to search for its contribution to the spectrum of an unknown sample. This proof-of-concept study utilized HAMAND to detect bloodstains on denim, a common substrate that produces a large interfering Raman signal. With HAMAND, we were able to successfully detect small traces of blood on denim. Subsequent preliminary tests were run to determine the applicability of the program to detect and differentiate bloodstains of different ages and distinguish between blood and other body fluids and potential false positives. The results indicate that HAMAND is not currently capable of performing these tasks. This methodology appears to have similar levels of accuracy to current biochemical tests for body fluid identification, but still has the distinct advantage of being nondestructive and rapid.

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