By Pawel Koscielniak, Jagiellonian University in Krakow
The general public believes that the largest role in combating crime is that of the police, followed by that played by representatives of the judiciary: judges and public prosecutors. The contribution of specialists in other fields, such as criminology or forensic medicine and psychology, is also fairly obvious and appreciated by the public. But chemistry? Do experts in chemistry have a role at all in solving crimes?
To answer the question, let us take a look at the Laboratory for Forensic Chemistry in the Faculty of Chemistry at the Jagiellonian University, Krakow, Poland. It is the first — and so far the only — research and teaching unit in forensic medicine in any Polish university.
At first sight, the scene we encounter is nothing like what most people imagine a chemistry laboratory to be: we find ourselves in an air-conditioned room in which the laboratory benches are covered not with the typical jars of reagents and test tubes containing liquids of different colours but with elegant, gleaming ‘black boxes’ that house precision measuring instruments. These are the basic tools of the trade of the forensic chemist — instruments that can analyse the detailed chemical composition of a variety of materials, which may be linked to a crime.
One of the most useful — and also the most expensive — of these analytical measuring instruments is the liquid chromatograph, which is ideal for detecting even small traces of widely used substances such as narcotics, ‘legal highs’ and medicines that, when taken in excess, can threaten human life. A liquid chromatograph needs only a drop of the liquid in question to tell, within 10 – 20 minutes, not only what it is but also how much of it is present in the material under examination. At the time of our visit, a drop of blood is being tested to determine whether it contains any psychotropic drugs. It is a sample taken from a woman suffering from depression, who was being treated with a drug containing tricyclic antidepressants. The amount of norclomipramine found in the sample showed that the dose was so high that it proved fatal.
On the other side of the laboratory, a microgram (which is one-millionth of a gram) of coloured printing ink is being collected from a document suspected to be a forgery. That minute sample is analysed by an apparatus that works on the principle of capillary electrophoresis: the image on the computer screen identifies the compounds that give the ink its characteristic colour. All we need to do is to compare the results with those obtained from a tiny sample taken from the authentic document. And if that does not resolve the problem, we can turn to something far more sophisticated: a spectrometer fitted with a high-power laser beam, which can be focused directly onto a line of handwriting from the document in question and also from a document known to be genuine. Comparing the elemental composition of the two samples can settle the issue.
In another case, capillary electrophoresis has shown a suspected bus ticket to be a forgery: the ticket looks genuine but was printed on an inkjet printer. The instrument is smart enough to pinpoint the make and the model of the printer — a Canon Pixma iP4500.
However, not everybody can use these modern precision instruments; it takes not only appropriate qualifications but also keen intuition that can come only after considerable experience. The painstaking work is often its own reward, especially when you detect something that seemed almost impossible to detect. And yet, the chemists who work here do not consider themselves detectives of the traditional kind but are quick to emphasize that their primary task is neither to solve crimes nor to prove the guilt of their alleged perpetrators but only to analyse objectively whether the materials in question are linked to the crime.
As befits a research and teaching establishment, the staff are always striving to do better, to find out how forensic examination can deliver more reliable results. And those who come up with new ideas are not always experienced chemists but also young scientists fired with enthusiasm for forensic chemistry. The researchers conduct many experiments and trials to develop new and improved analytical methods, which are then used in solving particularly difficult cases. Such practical application of research provides the researchers, especially doctoral students, with the opportunity to see how the knowledge and skills they have acquired are useful in solving major problems.
As you leave the Laboratory for Forensic Chemistry, you realize how necessary and important it is: both for the people who work there, because it fulfils their desire to explore and for us all, because it makes society a safer place.
Pawel Koscielniak
Jagiellonian University in Krakow
www.atomiumculture.eu
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