Infrared and Raman Spectroscopic Characterization of Hair Samples as a Forensic Evidence
Disciplines
Analytical Chemistry
Abstract (300 words maximum)
On any given crime scene, the chances of hair being recovered are very likely. In spite of its commonality as forensic evidence, hair is not fully utilized due to its limited analysis in forensic labs. Typically, the evidence will be examined through hydrolysis, which results in the sample’s destruction, or through microscopic techniques. Although both are useful methods of analysis, there is still a plethora of information available through other means of characterization. The goal of this research is to preserve a given sample while seeing if different types and colors of hair dye can be characterized through FT-IR and Raman spectroscopic methods. The data gathered through both methods revealed similar trends within each color group. In the Raman spectra, two moderate peaks around 1450 cm-1 and 3480 cm-1 correspond to the presence of an aromatic ring and an amine, respectively. Also, a very weak stretching around 3125 cm-1 indicates either an alcohol or phenol. The IR spectra yielded a broad and intense peak at 3250 cm-1 belonging to the O-H stretch of either an alcohol or phenol group. Additionally, the existence of two strong peaks around 1500 cm-1 demonstrate the presence of the C=C stretch of an alkene and three small peaks around 3000 cm-1 show the presence of C-H stretching. Lastly, indicating the presence of an amine’s N-H stretch, two relatively broad peaks are located in the fingerprint region of the spectrum around 1000-1250 cm-1. Although each individual method of analysis offers limited information, the combined data from multiple characterization techniques of a hair sample could prove invaluable to the world of forensic evidence.
Academic department under which the project should be listed
Chemistry and Biochemistry
Primary Investigator (PI) Name
Mohammad A. Halim
Infrared and Raman Spectroscopic Characterization of Hair Samples as a Forensic Evidence
On any given crime scene, the chances of hair being recovered are very likely. In spite of its commonality as forensic evidence, hair is not fully utilized due to its limited analysis in forensic labs. Typically, the evidence will be examined through hydrolysis, which results in the sample’s destruction, or through microscopic techniques. Although both are useful methods of analysis, there is still a plethora of information available through other means of characterization. The goal of this research is to preserve a given sample while seeing if different types and colors of hair dye can be characterized through FT-IR and Raman spectroscopic methods. The data gathered through both methods revealed similar trends within each color group. In the Raman spectra, two moderate peaks around 1450 cm-1 and 3480 cm-1 correspond to the presence of an aromatic ring and an amine, respectively. Also, a very weak stretching around 3125 cm-1 indicates either an alcohol or phenol. The IR spectra yielded a broad and intense peak at 3250 cm-1 belonging to the O-H stretch of either an alcohol or phenol group. Additionally, the existence of two strong peaks around 1500 cm-1 demonstrate the presence of the C=C stretch of an alkene and three small peaks around 3000 cm-1 show the presence of C-H stretching. Lastly, indicating the presence of an amine’s N-H stretch, two relatively broad peaks are located in the fingerprint region of the spectrum around 1000-1250 cm-1. Although each individual method of analysis offers limited information, the combined data from multiple characterization techniques of a hair sample could prove invaluable to the world of forensic evidence.