A cutting-edge technique to identify human hair could one day be helping to catch criminals according to a new study from researchers in Canada.
The tool produces results faster than current DNA analysis techniques used in law enforcement, and in early tests showed a 100% success rate at identifying gender and ethnicity.
The new tool is the work of Diane Beauchemin, a professor in the department of chemistry at Queen's University in Kingston, Ontario, and MSc student Lily Huang. They describe their proof of concept study in the Journal of Analytical Atomic Spectrometry.
Prof. Beauchemin says her first "foray into forensic chemistry was developing a method of identifying paint that could help solve hit and run cases." Applying a similar approach to hair analysis was Ms. Huang's idea, she adds, so they started working on it last year.
Blood samples recovered at a crime scene are often used to identify gender and ethnicity, but blood deteriorates quickly and is prone to contamination.
However, hair is very stable. The reason it is a promising avenue for forensics is because of the unique mix of elements it contains, which varies according to diet, ethnicity, gender the environment and working conditions. They get into the hair from sweat secretions.
The team found they could identify gender from the elements magnesium, sulfur, strontium and zinc. And to discriminate ethnicity they used lithium, molybdenum, sulfur, strontium, chromium, potassium, nickel, zinc and lead.
The process takes just 85 seconds to complete. First they grind up the hair sample, burn it (using a method called electrothermal vaporization), and then analyze the vapor it produces (using inductively coupled plasma optical emission spectrometry).
Current forensic methods used to analyze hair are time-consuming and use corrosive solvents and reagents, Prof. Beauchemin told Chemistry World.
Method is robust and can be used universally
Ms. Huang says the method is "very robust and can be used universally. One of our samples even included dyed hair and the test was 100% accurate. The test was able to distinguish East Asians, Caucasians and South Asians."
Current forensic methods used to analyze hair are time-consuming and use corrosive solvents and reagents.
The team is already talking to law enforcement agencies about the next step in using the new method.
And the researchers are also planning to develop the method so it can pinpoint exactly where in the world a hair sample is from, as well as add more ethnicities and age to the repertoire.
To extend the repertoire of variables the method can identify means measuring more elements, but Prof. Beauchemin says this would not take more time, because their detection is simultaneous.
In 2010, Medical News Today learned how researchers are working on a method of forensic identification using hand bacteria. The method uses the fact that when we handle objects we leave behind bacterial communities that are uniquely identifiable.
Written by Catharine Paddock PhD