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Facilitating The Work Of Forensic Scientists

April 4, 2012

A method to speed up gunshot residue detection and another capable of identifying antipsychotics in the brain are the latest pieces of work of the Metabolomips group of the University of the Basque Country

The University of the Basque Country’s (UPV/EHU) METABOLOMIPs group develops analytical methods to help characterize different types of substances, and focuses on the forensic sciences, in particular. For example, they have just developed a methodology for detecting gunshot residues which comes up with the results in record time, and thanks to this they have had a paper published in Analytical Chemistry, one of the journals that has the broadest impact in this discipline.

This group belongs to the Department of Analytical Chemistry of the Faculty of Pharmacy and comprises chemists, pharmacists, food technologists, etc. Its name, METABOLOMIPs, points to its two main areas of interest: metabolites and MIPs: “We deal mainly with research into biological fluids relating to forensics or drugs, and the compounds we do research on for this purpose tend to be metabolites. Another section of the group works on the development of electrochemical sensors to determine the metabolites, and these sensors are of the type known as MIPs [molecularly imprinted polymers],” explains Ramón J. Barrio, the head of the group.

On these two bases they work on different lines of research linked to food safety (the study of oenological matrices, etc.) or environmental analytical chemistry (emergent contaminants in waste water, etc.) but they make the point that what most characterizes them is the field of analytical chemistry relating to bio-health and, in particular, the forensic discipline. In fact, Barrio is also the director of the Master’s in Forensic Analysis course run by the UPV/EHU.

Gunshot residues

Gunshot residue detection is used to identify the person who pulled the trigger (the residues get stuck to the hands, for example) or to distinguish between a suicide and a murder. If it can be applied, the innovative methodology being proposed by METABOLOMIPs has greater advantages in terms of time and cost than the one currently being used in forensic laboratories. “A technique based on electron microscopy has existed up until now to see whether the shot was fired by a certain individual. It is very expensive and each analysis takes between eight and ten hours. We have come up with one in which we can produce reliable analyses within an hour,” claims Barrio.

Instead of using electronic miscroscopy, this method involves a technique combining laser ablation and mass spectrometry (LA-ICPMS) to detect metals and isotopes unique to gunshot residues. It starts by gathering the inorganic residues found on the skin of the person suspected of firing the shot, the laser extracts the material from the surface, and mass spectrometry measures the presence of these metals and isotopes in it. According to the article, this technique would enable smaller residues to be worked on, it would be more straightforward, cheaper and faster (less than 66 minutes), and its effectiveness in four types of firearms has been proven.

Antipsychotic drugs in the brain

But the paper on gunshot residues is not the only one that METABOLOMIPs has had published recently. The journal Forensic Science International has reported on another analytical method developed by this group, in this case to determine the presence of psychotic substances in the human brain and designed to be used in the forensic area, specifically in post mortem diagnostic tests. “We have developed a methodology to determine a series of drugs that are prescribed to treat schizophrenia and different types of psychosis. The aim is that when a person dies for forensic reasons, it is possible to analyze and decide whether these substances have accumulated in his or her brain,” says Barrio. And the fact is, when a person needs lifelong treatment of this kind, it can lead to consequences that can even be linked to his or her death: “When these substances accumulate in the brain, they can cause other dysfunctions, like neurodegenerative disease. And we have even thought that they could lead to suicide, although many analyses have to be done to prove that.”

One of the things that Barrio highlights in this article is that they have been working on matter that is very difficult to get hold of: the brain. Specifically, they have used the UPV/EHU’s brain bank, and all the samples analyzed have come from suicide cases. METABOLOMIPs have developed this method for Cibersam, the Networked Biomedical Research Centre devoted to Mental Health. And another point that should be highlighted is team work, going beyond the group even. In the field of neurosciences, as in this case, they are working together with Javier Meana of the UPV/EHU’s Department of Pharmacology. “Our mission is to produce a data base with sufficient samples of compound compositions in the brain, and not just of anti-psychotic drugs,” he concludes.

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