A Selective Food Directive

Tell us about your current position!

I’m currently professor of analytical chemistry at Wageningen University, and I’m also the principal scientist at the applied research institute Wageningen Food Safety Research (WFSR). As principal scientist, I’m responsible for the strategy of the R&D program – so I am involved in things like chairing our research committee, coaching talent and advising the board on strategic R&D decisions. It’s a multidisciplinary institute, so our activities range from analytical chemistry to toxicology, microbiology, and data science. In addition to these roles, I am also coordinator of the European MSCA ITN project FoodSmartphone and co-chair of the Recent Advances in Food Analysis (RAFA) symposium series.

What are some of the highlights from your career in analytical chemistry?

I have a long history in analytical chemistry. I started out four decades ago doing my master’s research at Leiden University. At the time, we were developing low-dispersion post-column reactors for HPLC – this was before LC-MS was invented of course – and the idea was to address some of the selectivity challenges with current HPLC-UV methods by performing chemical reactions after the column. Alas, these reactors had issues of their own. We ended up solving a lot of them by developing segmented-flow reactors that enabled longer reaction times and, eventually, even performed on-line immunoassay detection after HPLC for the first time. That was a highlight of my early career that has influenced my later research, combining instrumental analysis with biorecognition assays.

After my master’s, I did my PhD at the Free University of Amsterdam, where I became interested in bringing additional selectivity to HPLC-UV via on-line SPE. I then spent 10 years in industry at AkzoNobel. That was an amazing period in my career, because I spent a lot of time exploring novel technologies. I managed to convince them to get one of the first API-MS systems, because we were encountering a lot of impurities -thanks to the separation power of the new technique CZE- and struggled to identify them. This turned out to be quite an achievement; we ended up proving that electrospray ionization could be used for not only small molecules and proteins, but also synthetic polymers. Later on, we combined this with MALDI MS and ended up producing one of the most widely cited review papers on the subject. After my time in industry, I came almost full circle in my career by returning to academia. Now, once more, my focus is on selectivity in analytical chemistry.

You refer to “selectivity” as a common thread throughout your career. Can you tell us more?

To me, there are three fundamental questions in analytical chemistry: What’s in there? How much is in there? And where exactly is it located? That first question is essentially the issue of selectivity and it’s something I’ve focused on in many different ways. To illustrate what I mean, I’ll use an example from my time as an expert witness in a specific court case for the government. Once, the judge asked how I could be sure that there was no other molecule on the planet that would yield a similar LC-MS signature to the banned substance under investigation. I’d never thought about it like that. Until that point, we’d followed the official EU legislation – determining retention time, checking against reference standards, determining the relative abundances of certain ions, and checking that they didn’t deviate too much. So this really got me thinking.

In the years following that case, one of my PhD students worked on a way to give a quantitative measurement of the selectivity of an LC-MS result. He derived empirical relationships between all kinds of molecules in databases across the globe and came up with a probability function that we could apply and tell the court, essentially, how (un)likely it was that another molecule could mimic the result given as evidence. This nicely illustrates what we mean by selectivity.

What do you love most about what you do?

I find what I do really fun; that’s what keeps me motivated. In general, I would say that I love the design of instrumentation and working toward simplicity. In the 1980s, during the glory days of my PhD, I worked on designing an in-line solid phase extraction cartridge built into the axis of a micro-LC injection valve. That one never made it into a commercial product, though similar designs would later be released. But it was great to come up with a prototype SPE cartridge exchanger that is still on the market in a fourth-generation instrument. In a similar vein, our current team is working on smartphone-enabled ionization by using the USB port of the phone to provide 1.5 volts to an inexpensive transformer board/HV generator that supplies several kilovolts to a coated metal blade for direct electrospray of samples into a transportable MS. Again, it’s this combination of instrumental design and simplicity (costs less than 10 USD) that I really enjoy.

What drives you?

I have two main drives. First, I really enjoy the development and growth of young people – my students and PhD students. I like to see them gradually coming up with better ideas than I ever could myself; it’s amazing! My second driver is seeing instruments designed with the “KISS” principle in mind – keep it simple, stupid. I love that saying and it has stayed with me throughout my career. I constantly come across new research that follows this principle and it renews my love for the field. For example, one of my university colleagues recently came up with an amplification assay for genetic material that worked in what was essentially an espresso cup. There was no requirement for special heaters or thermal cycling; you just applied the sample to the cup and placed it into hot water. It’s incredibly simple, it worked, and I think that’s fantastic!

What keeps you awake at night?

Mainly rather crazy ideas and concepts, but in the past court cases kept me awake because they were stressful situations. More generally, I don’t like how scientists’ integrity is often called into question. Your position as an expert witness is obviously independent in a court case but, quite often, it turns into a debate about the expert’s own integrity and that of their institution. It’s something I don’t like to see happen.

What is your message to today's analytical scientists?

We need to learn how to improve our communication with target audiences. People should be aware – whether the audience is a group of scientists, marketers, industry people, or the general public – of how to correctly communicate the work they are doing. One of the key things we should be looking to develop in young scientists is the ability to deal with the doubts around lab testing. It’s not only an issue in court cases; in general society, we see that governments and scientists are being trusted less and less. As analytical scientists, we cannot ignore that situation and we certainly have a role to play in remedying it. From my perspective, it would be beneficial to build aspects such as social science, psychology, and marketing techniques into our analytical education.