The group of researchers of St Petersburg University headed by SPbU senior research fellow and Candidate of Chemistry Vladimir Kochemirovskii has developed a new method to examine the ink of the ballpoint pens and gel pens to identify when the signature was made unless it was made no more than 100 months ago.
Published in the Applied Sciences, the research findings help the lawyers to investigate the most difficult cases.
Today, ink chromatography is a method in forensic ink analysis. Its essence is when ink is exposed to certain solvents the colors dissolve and can be separated out. The older the paper, the less components remain on it. It also has its drawbacks: when the paper is more than two years old, the solvents completely disappear, and a 15-year-old document is impossible to analyse. How long the solvents evaporate depends on the level of humidity and temperature.
SPbU scientists has come up with a new idea: to analyse the ink itself, rather than the solvents, as in most pens ink is a mixture of three dyes. They study how they react with ozone in the oxidation reactions the concentration of which remains stable in the atmosphere. The Raman spectroscopy makes it possible to work with the documents that were created from 20 to 100 months ago. The error is now six months, but the scientists are striving to decrease it to a couple of months.
“Fake documents are made everywhere, — said the Director General of the Small Innovation Company “Laser Chemistry” Vladimir Kochemirovskii. — How we can prevent making fake documents is an acute problem, still there are few methods to analyse inks. We have developed a new one that has become possible using the equipment the Research Park offers. To be able to measure is not enough. Should we want to make it a forensic ink analysis, we need to consult the lawyers”.
The lawyers play a vital role in the research, as it is primarily concerned with how to make the expert forensic evaluation of the documents more elaborate. In September, SPbU signed an agreement with the Russian Investigative Committee to carry out joint research project, exchange experience, and develop expert evaluations.
Forensic analysis of the documents are popular today, but this new method will bring more opportunities in investigating criminal cases.
SPbU Professor Natalia Kirillova
“Our colleagues from the University have carried out about 60 evaluations in different regions of the Russian Federation. It is vitally necessary in the civil and arbitrary cases, but in the criminal procedures as well. After the research findings have been published in the international journal, our experts have been asked to perform expert evaluations from abroad” — said SPbU Professor, Doctor of Law Natalia Kirillova.
Signatures, stamps, printed texts and even paper are at the focus of our researchers. They are often asked to reveal when and how the document was created. Vladimir Kochemirovksii, SPbU Associate Professor Andrei Tverianovich and their colleagues evaluated the originality of the magazines that comprised information how it was eliminated and located in the region of Chernobyl disaster. It revealed that in 2000s in the documents there were added “fake” people who suffered from the disaster. The method can be used on the arts to reveal hidden signatures and to define the age of the object.
Much is still to be done both for chemists and lawyers, say the scientists. First, the questions should be more clearly stated: sometimes they are like “When was the document created?” As the time when the document was stamped or printed can differ, so to identify when the document was created is difficult.
You can use the sample for comparison: signatures on the documents which have been stored at the optimal temperature and level of humidity. However, according to the current legislation, the experts cannot collect the evidence. So the experts proposed to create a collection of the document samples: samples with various inks, papers that were created at definite time. How to make it legal? It is up to the law to decide.