The ability to determine the freshness of prints is very important, for example, for forensics. If successful, the refinement of the new assessment method, the practices based on it can be of great help to the experts.
Scientists at Iowa State University were able to find a way to determine the time that has passed since the fingerprint was left. They published an article about their discovery in the journal Analytical Chemistry.
Chemist Paige Hinners, who was working on another method of checking the age of the left fingerprints, accidentally discovered that the unsaturated fatty acids triacylglycerols eventually disappear from the list of substances fixed in fingerprints. After careful testing, it turned out that they are being replaced by other substances.
It turned out that the degradation of triacylglycerols occurs in fingerprints when interacting with ozone. Based on this fact, the researchers created a tool to determine the age of a fingerprint.
The elapsed time from the appearance of the fingerprint can be determined using matrix-activated laser desorption / ionization mass spectrometry (MALDI). It is a technology that uses a laser to analyze the compounds left on a surface, and then records the mass and electrical charge of each component in the sample - for example, various oils in a fingerprint. The imaging tool allowed chemists to track the degradation of unsaturated oils when they react with ozone in the air.
While the method of determining the age of prints is still at the very beginning of the creation and customization process, but scientists are optimistic: it shows itself quite well. “Right now, we can measure the number of days [since the print was made]. It is easy to distinguish one-day from fresh. There is no doubt about that,”says Dr. Hinners. Also, the advantages of the method include the fact that the powder used for fingerprinting does not interfere with determining the age of the fingerprint and does not violate the determination of its composition.
However, you shouldn't expect the new forensic super tool to be in use tomorrow. So far, the study was carried out on a very small sample, and a lot of factors affect the chemical composition of fingerprints. Time-consuming work is required to establish how the method will work in different climates, in the prints of people of different ages, gender, ethnic groups and taking into account individual characteristics. To date, scientists have achieved confirmation of the concept itself and consistent results when testing each person.