Crime scene lipstick now traceableMarie Donlon | October 24, 2021
Identifying brands of lipstick left behind at a crime scene — for instance, on glasses, tissue or cigarette butts — thereby potentially tying a suspect or victim to a crime scene, can now be accomplished thanks to a technique developed by scientists from the University of Kent in the U.K.
Without having to remove evidence from an evidence bag and potentially contaminating or destroying it, the Kent team used Raman spectroscopy — a process that involves the vibrational energy and light of chemical bonds — to analyze the lipstick residue.
According to the researchers, the lipstick, like other materials, scatters light, generally at its original wavelength. Yet, a minute proportion is scattered at different wavelengths thanks to changes in the vibrational energy of the lipstick's molecules.
Using a microscope, the light is gathered to give a Raman spectrum that depicts a characteristic vibrational fingerprint. This fingerprint can then be measured against a rainbow of lipsticks of assorted brands and types.
The study, "Application of Raman spectroscopy for the differentiation of lipstick traces," is published in the journal Analytical Methods.