Raman effect to help nab criminals

 Since DNA testing of samples from a crime scene is time consuming, scientists have found a way to analyse hair samples at crime scenes using surface-enhanced Raman spectroscopy (SERS).

IANS| Last Updated: Feb 19, 2015, 17:14 PM IST

New York: Since DNA testing of samples from a crime scene is time consuming, scientists have found a way to analyse hair samples at crime scenes using surface-enhanced Raman spectroscopy (SERS).

The results would help scientists determine quickly whether it was coloured and the name of the dye brand used.

"This highly sensitive technique could help forensic investigators analyse hair quickly in the field," said lead researcher Richard P. Van Duyne from Northwestern University, United States.

"Analysing hair for forensic investigations, despite what TV shows would have you believe, can be a labour-intensive and flawed process,"Duyne and co-researcher Dmitry Kurouski said.

Testing samples for DNA requires an intact bulb or root, which isn't always present. Plus, the procedure is time-consuming, which can cause a large backlog of cases.

So investigators often used the more traditional method of visually comparing hair from a crime scene with samples from suspects using a microscope. But this technique doesn't necessarily provide conclusive results.

Van Duyne and Kurouski wanted to find a more practical and accurate way to analyse hair. The researchers turned to surface-enhanced Raman spectroscopy (SERS) with a portable Raman spectrometer.

SERS can detect minute amounts of illicit drugs, explosives, gunshot residue and body fluids.

With this method, the team could rapidly confirm whether hair samples, including the microscopic ones, were dyed and find the brand name of colourant used.

The report appeared in the journal Analytical Chemistry.