Portable forensic tool identified for human hair analysis

Near infrared spectroscopy (NIRS) has the advantage of being readily available and Sarina Brandes from Queensland University of Technology has demonstrated that this portable technique could be used to analyse hair for forensic purposes.

A chemistry Masters researcher, Brandes said this method was independent of analysis of DNA, which could break down quite quickly, especially at disaster scenes such as after a tsunami.

Her supervisor, Dr Serge Kokot, who has researched the forensic possibilities of human hair analysis for the past 12 years, said human hair could survive relatively harsh environments, where DNA couldn't.

"NIRS has been found to need only a few millimetres of a single hair for analysis but, until now, we have not had the ready capacity to apply this technology in harsh environments," Dr Kokot said.

"Ms Brandes' achievement is several fold: it opens the door for on-field measurements, it provides a method for analysis of hair after immersion in water, and it also has the advantage to readily differentiate a naturally coloured hair from that treated with a hair dye to give a similar colour."

Dr Kokot said Brandes' technique could obtain the infrared profile from only a tiny part of a strand of hair and then interpret this profile using specialised mathematical methods to compare it with similar profiles collected from suitable reference hair samples.

"The results can be displayed in an easily understood diagram and/or the profiles can be rank-ordered and the position of the tested hair can be established relative to the reference samples," he said.

"In this manner, Sarina's technique can establish a person's gender, race and whether they had chemically treated their hair, as well as what the original hair colour was."

Dr Kokot said the use of Brandes' research could help to identify victims of natural disasters, like tsunamis, where hair has been in water.

"Other useful spin-offs have been that Sarina's technique can also identify what type of water the hair was found in, like seawater, and how long the hair had been immersed in it," he said.

"Hair found at a crime scene could be matched against hair found in a comb of the victim, which can be used as the reference sample, or it can be compared against hairs from suspects in a similar manner."

Dr Kokot said portable NIRS instruments were available and could be used at a crime or disaster scene.