FORENSIC IDENTIFICATION OF SINGLE DYED HAIR STRAND NOW POSSIBLE

In a recent study, scientists at TOKYO UNIVERSITY OF SCIENCE, JAPAN, have combined two modern techniques, called SERS- Surface Enhanced Raman Spectroscopy and XRF- X-RAY FLUORESCENCE, to distinguish between different colors in individual hair strands. A single strand of hair can be of major significance in the progression of a trial, especially when root cells are found attached- a rare scenario. Although mitochondrial DNA can still be analyzed from the hair shaft, but such tests are not sufficiently reliable to identify a person and usually calls for corroborative evidence.
Leveraging the era of fashion consciousness, scientists developed a strategy for identifying criminals from a single strand of hair. Their approach involves finding out if two individual strands of hair belonging to the same person based on the composition of hair dye products found on them. To do this, they employed two well-known analytical methods: SERS and XRF analysis.
SERS is a special type of Raman spectroscopy that provides a “structural fingerprint” of material even when very few molecules are present in the target sample. SERS can easily detect the overall differences in composition between different types of hair dyes, such as permanent, semi-permanent, or natural dyes. However, it is not enough to distinguish between hair coloring products that contain or produce similar dyes. On the other hand, XRF analysis comprises irradiating a material with X-rays and examining the energies of photons re-emitted when the electrons in the sample leave the excited states. XRF analysis is principally useful to determine which metallic elements are used in the ingredients of hair dye products. Using both techniques, the scientists were able to easily distinguish between five different dyes applied to individual strands of hog hair.
Apart from narrowing down the range of suspects, these non-destructive techniques can be conducted using portable devices, enabling the investigators to do an on-site examination and save time.

SOURCE :- https://www.labmanager.com/news/forensic-identification-of-single-dyed-hair-strand-now-possible-24612