GC Orbitrap Guru Series: Dr. Kerstin Krätschmer

It’s been 10 years! Yes, in 2015 “gas chromatography” met “Orbitrap mass spectrometry” for the first time with the launch of the Thermo Scientific Q Exactive GC-MS/MS at ASMS (in St. Louis, Missouri). Over that decade of discovery, many scientists have delved into the world of volatiles analysis (yes, and semi-volatiles) using high-resolution accurate mass with Orbitrap technology. From POPs to PFAS, metabolites to microplastics, in samples ranging from meteorites to mackerel, scientists have made discoveries that have advanced our understanding of this “volatile” world.

In this new blog series, GC Orbitrap Guru Series, I am catching up with some of the scientists, analysts and people behind the technology to capture their science stories and experiences with GC Orbitrap mass spectrometry.

First up is Dr Kerstin Krätschmer, Project leader NRL POPs, researcher organic contaminants group at Wageningen Food Safety Research in the Netherlands.

Name: Dr. Kerstin Krätschmer

Organisation: Wageningen Food Safety Research

Job title: Project leader NRL POPs, Researcher Organic Contaminants

Top Applications: Food safety, chlorinated paraffins, dioxin, PFAS

Years with GC Orbitrap: 9

What did you study and where?
I studied food chemistry at Wuppertal University, which is known as Germany’s greenest city (I said you would learn something!). This was followed by legal training to gain state certification as a food chemist. My PhD focused on the analysis of polychlorinated alkanes, back then still known as chlorinated paraffins, at the European Union Reference Laboratory (EURL for POPs) in Freiburg, in cooperation with the University of Hohenheim (Stuttgart, Germany).

What was your first scientific job? (You actually got paid to do science?)
Haha, that was actually my PhD position – first with half pay, then later a full job as a lab manager position but did not involve much managing beyond my own lab work for quite a while. Though I did like working at the EURL POPs for the chance to network across all EU and associated states, and even the fiddly bits where you have to figure out why some customs department won’t let the proficiency test sample pass through! To balance the regulatory and networking activities, the aspect I liked most about this role was that there were plenty of opportunities for testing new instruments and methods.

What was you first scientific job? (you actually got paid to do science?)

What was the first mass spectrometer technology that you used?
Like most scientists I know, it was at university, we had a lab course module on instrumental analysis, where they let us, students, try out a wide range of technologies, though only under strict supervision. The first MS that I really got into on my own was the Q Exactive GC-MS/MS that I used for my PhD work. Keeping with the university tradition, and after almost five years of ups and downs, I named her Betty (Don’t ask why). 🙂

When did you first use GC Orbitrap MS and for what application?
That must have been 2016/2017, and then for setting up my method for polychlorinated alkane analysis, because those analytes are so complex, the full scan high-resolution data is the only way to go with them for academic purposes.

Why did you need GC Orbitrap for polychlorinated alkanes?
At some point, we calculated that the minimum needed mass resolution to avoid interferences was way beyond 20,000 resolving power; if you also wanted to look at other contaminants in the same sample, the resolution had to be even higher. The 120,000 resolving power available on the Q Exactive GC-MS/MS provided us with that analytical power that enabled us to see what otherwise would have been impossible.

What surprised you most about GC Orbitrap?
I was really surprised when I first saw the physical size of the Orbitrap part and realised just how tiny the actual Orbitrap is! You see this large box hiding the MS part of the instrument and automatically think this must all be this super-fancy detector, but then it fits comfortably into the palm of your hand. Mind-blowing!

How does GC Orbitrap help answer your scientific questions?
What would you like to see improved? (be honest) Today, with the ever-growing list of contaminants to be monitored and analyzed in food samples, we try to combine methods as much as possible. One such methods runs on the GC-Orbitrap, for two reasons: we can monitor many more target compounds than targeted methods such as GC-MS/MS, thanks to full scan mode, and ddMS² allows us to add some non-target screening on top, in case we’ve missed some new and upcoming contaminant that is not yet on our radar! Of course, all that doesn’t come without a pay-off: the more broadly you try to work, the less sensitive you are. So, a bit higher ionization efficiency or any other modification allowing for an increase in sensitivity without sacrificing too much mass resolution would be on my wish list.

And finally…What is the best conference venue you have been to and why? Oh, there were so many! I think I’ll have to go with Vancouver, BC, Canada, though. The 2017 Dioxin conference in Vancouver was my first international (and, indeed, trans-Atlantic!) conference as a presenter, and it was the 250^th anniversary of Canada that year! British Columbia is a culturally rich area with unbelievable variety in nature as soon as you leave the cities, but the vibrancy of the people there was what made the stay unique.

That’s a wrap (or blog actually). We’re thrilled to have had the opportunity to chat with Kerstin for my first subject of this series, GC Orbitrap Guru. I have to admit that I share your “wow” moment on both Vancouver and the physical size of the Orbitrap! I am on the hunt for other GC Orbitrap people, so if you would like to tell your story or just to share your GC Orbitrap stories with us, please reach out to me at dominic.roberts@thermofisher.com

Thirsty for more? Please take a look at the Thermo Scientific Orbitrap Exploris GC

Additional references:

Mézière and Krätschmer et al. 2020. Addressing Main Challenges Regarding Short- and Medium-Chain Chlorinated Paraffin Analysis Using GC/ECNI-MS and LC/ESI-MS Methods. Journal of the American Society for Mass Spectrometry 31: 1885-1895.

Visit us on LinkedIn: #GcOrbitrapGuru #gcms #DecadeofDiscovery