The fascination of molecules...and the diverse fields of mass spectrometry

A transfer discussion with the head of the Physical and Theoretical Chemistry working group, Prof. Dr Thorsten Benter

"It has become indispensable in the pharmaceutical industry, in biology, in analytical chemistry and in countless other fields. Mass spectrometers are used very intensively wherever work is carried out in the life sciences," says Thorsten Benter, head of the Physical and Theoretical Chemistry working group at the University of Wuppertal. But what exactly is a mass spectrometer?

A mass spectrometer is a measuring device that can determine the mass of electrically charged atoms and molecules. The molecules to be analysed are transferred into the gas phase (e.g. by desorption or evaporation) and then ionised. The entire process is then called mass spectrometry. There are 25 different types of mass spectrometers in use in physical and theoretical chemistry alone.

Why chemists are interested in mobile phones

Professor Benter knows how confused the layman reacts to his work and uses two examples to explain the areas in which this special research device is used. "One story we're looking at," he says, "is the etching process for semiconductor production. Every one of us has a mobile phone. But hardly anyone thinks about where the performance of these devices actually comes from," he explains. The small chips in our mobile phones are becoming more and more powerful because more and more microstructural components are being integrated. "This doesn't mean that anything is built into them," explains Benter, "but rather that you take a macroscopically large structure, expose it with a certain pattern, place this exposed material in an etching system and etch away wafer-thin layers. It is then exposed again on the outside and returned to the system. This creates wafer-thin layers on top. And so the etching and deposition of substances is almost atomically precise." And this is exactly where the work with the mass spectrometer comes in. The chemical processes that lead to the creation of such a chip work with etching gases, which are very aggressive. Among other things, mass spectrometry has to tolerate corrosive gases that ablate surfaces. It must therefore be able to withstand a very harsh environment and at the same time recognise the end point of an etching process with high sensitivity and speed. "Whenever I come across a layer that I don't want to attack," he explains, "the mass spectrometer has to stop the process and recognise that this layer needs to be preserved. In technical jargon, this is known as endpoint determination."

Use in doping control

Another area of application for mass spectrometry is doping control. Here we are dealing with biological fluids that are first prepared. "Let's assume that the preparation has gone well, then what is left of the sample must first be injected into a pre-separation stage and then, after the pre-separation, introduced into the mass spectrometer again." In these procedures, the device should ionise as gently as possible because the active substance to be analysed reacts very sensitively.
Born in Schleswig, he combines physical chemistry with theoretical chemistry in his working group. And for good reason. "Physical chemistry would like to create molecular order in the world," and because scientists can only imagine what molecules do and what they look like, but these are not visible or tangible, theoretical chemistry tries to use mathematical models to make precisely the molecular image that the researchers imagine from the macroscopic world calculable. "And from these predictions, which the calculations then allow, we check whether our picture is correct."

The why question

The Wuppertal working group has a specific research goal in mind. "For us, this is ion-molecule chemistry," says Benter. "For example, we have chosen cluster formation - a cluster is a collection of atoms and molecules - as one direction. Not so much is known about this chemistry. We have certain questions in this research objective. We know from various observations that cluster chemistry plays a major role in modern mass spectrometry, but we find little or no clusters at the detector of the mass spectrometer. So something must have happened to them. So why don't we see them? And that's the first approach. The why question."
In order to be able to work on this why question, many experiments are required, which in turn are often very expensive. And so, in addition to their research work, the scientists are always on the lookout for money, contacting companies or public sponsors. In doing so, they manage the balancing act between the demands of business, which wants to sell, and the interests of science, which wants to understand in order to get closer to its goal.

I have little fear of failure

Not every research goal leads to success. But for Benter, a goal that is not achieved is not a failure at all. "I have little fear or concern about failure," he says clearly. "If we realise that we are not making any progress on a path, then that is a realisation. Today, it is often not viewed positively, but rather as failure. That is a completely wrong perception." Every hypothesis must be verified or falsified. The scientist says: "If I only ever assume that the answer will be positive, that what I have already thought up will be confirmed, then it is the answer to my question in advance." And that's not the point. "The positive result is self-affirmation. The surprising result, which was not expected, gives you the opportunity to think and go in completely new directions. That often happens, especially in this area of research where we work. And that's a lot of fun."
Benter would therefore also like to see more scientific journals publishing precisely these "failed" results. "There are now very few journals that actually publish negative results." This would mean that many experiments would not have to be carried out again and again at universities. The chemist says with amusement: "Everyone writes about how great they are doing. Everyone writes about how great it went. Nobody writes that it didn't work, please don't do it like that because it won't work. Being able to read this would be very important for other scientists", because the pool of experiments that have developed differently to the original hypothesis is large and offers many insights.

The vision of a mass spectrometer for the home

In Benter's opinion, mass spectrometry can be used in countless areas, as reported at the beginning. And the scientist also believes he can recognise a future trend. "If you go to conferences, you can now see that there is a very strong trend towards making mass spectrometers smaller and smaller. The big companies are very keen that you can practically wear mass spectrometers on your body to check your own health. This is clearly a development path towards being able to take miniaturised devices with you everywhere."

Science in conflict with politics...

Scientific findings are unambiguous. It is therefore often difficult to understand why politicians do not implement these findings. Benter describes this problem with a simple example: "I myself sit in the laboratory and measure something and say on the basis of my findings: mankind must stop driving cars. On the other hand, there is the employer, who expects people to come to work on time." So what to do? For Benter, the first step is to create a level playing field. "A person who works in politics has a completely different socialisation than a person who works in science. I believe that politics is about many things that a scientist cannot imagine and vice versa. Politicians also always look at people's needs and they want to be re-elected. People want a certain quality of life. Scientists often have this bare datum in mind." The 58-year-old is in favour of communication. "If we say we want to abolish cars, then that's simply not possible without further ado, but we have to find ways to gradually find a solution to the transport problem for people who want to get from A to B. A solution that doesn't necessarily have to be a car. A solution that does not necessarily rely on combustion engines or private transport, but perhaps also on other options."
And the Wuppertal scientist remains optimistic. "When I was still really travelling, in 'my' Greenpeace days, people said that we would never achieve 20% renewable energy. Today we're at 50% and the forecasts we're already getting are heading towards 60 to 70%. So it is possible. It's not just a pipe dream. The pressure just has to be great enough and then people become incredibly inventive."

Fascination with molecules

Anyone interested in Benter's degree programme should be fascinated by the changes in the molecular world. "If you find this in any way fascinating, wanting to understand why something happens macroscopically that actually happens at a molecular level," is the first basic requirement. "Everything else," concludes Benter in a relaxed manner, "comes naturally."

Uwe Blass (interview from 29 January 2019)

Prof Dr Thorsten Benter studied chemistry at Kiel University from 1982 to 1987 and obtained his doctorate there in 1993. His scientific work took him to the University of California, Irvine for four years in 1997. He has been Head of Physical and Theoretical Chemistry at the University of Wuppertal since 2001 and represents it in research and teaching.