Phd in the Spotlight: Hanneke Brust
Hanneke Brust (1986) will be awarded her doctorate degree at the UvA on 25 June. As part of her doctoral research at the Van ’t Hoff Institute for Molecular Sciences (HIMS), Brust made chemical profiles of explosives. These profiles aid in establishing if there is a relationship between explosives found at a crime scene and at a suspect's home.
What did you do?
‘I did chemical dissections of different types of explosives found at crime scenes, for example in gas attacks on ATMs. If the explosive substance is made up of the same materials as those found at a suspect's home, a link can be established between the two. I studied four substances that are often used to make explosives in detail – their abbreviated names are HMTD, AN, PETN and TNT. Using different analysis techniques and mass spectrometry as the detection method, I established the level of impurities, degradation products and isotopes in samples of explosives. Each type of explosive contains different quantities of these, which is caused amongst other things by the use of different synthesis methods and conditions. By studying this variation, I was able to create chemical profiles for explosives that are characteristic of the origin of those explosives. That has never been done on this scale before.’
Can you use these chemical profiles to solve cases?
‘No, but that's not the task of forensic experts. We look at the similarities in chemical profiles in order to try to establish whether an explosive at a crime scene and an explosive that has been found at a suspect's home have the same origin. It's then up to the legal experts to identify the suspect as the perpetrator. There are two ways to establish a link between an explosive and a suspect. If the explosive is still intact, we look at the impurities and the isotope ratios in the substances. If the explosive has been detonated, we look at the substances that were created during the explosion: the degradation products. These can also occur through natural degradation. By examining the ratios of these degradation products on a suspect's clothing, you can establish whether the suspect was present during the explosion.’
Was it like being on CSI?
‘Not really. I never went to any crime scenes. I did my work in the lab. On the other hand, CSI is not very realistic. The entire investigation is done by one person, while in reality all kinds of people are involved. The police investigate the crime scene, another expert studies the DNA in the laboratory, another the explosives in a lab, and so on. And the investigation takes a few weeks rather than a day as in CSI.’
How did you end up in forensic science?
‘My background is in chemistry: I did my Bachelor's in Chemistry at Utrecht University. After that I wanted do applied research with a clear social link. That's why the Master's in Forensic Science at the UvA appealed to me so much. My supervisor, Peter Schoenmakers, asked me if I'd be interested in starting this doctoral position with him while I was still doing my work placement. I want to continue in analytical chemistry, but that doesn't necessarily have to be in forensics. I'd prefer to work in the business sector. As long as I can research how things are put together.’
Author: Carin Röst