Our machines also regularly have their say: today we are talking about a gel permeation chromatograph, i.e. a machine that can be used to determine the size distribution of molecules and is used at Hof University of Applied Sciences for basic research.
The machine has been in use here since 2024. It is supervised at the Institute for Circular Economy of Bio:Polymers (ibp) by Johannes Küfner and Benedikt Hiller, both research assistants, David Krieg, deputy research group leader and Lucas Großmann, deputy head of the institute.
Hello, a first question to warm you up: Who are you? Please introduce yourself briefly.
“Welcome to my glass palace! From here I have a view of my entire empire, the laboratory in B206. By the way, my glass palace is the fume cupboard in which I was built. You can enter through its main portal, the sash. However, as I work with volatile solvents, I can only grant you a brief audience, then you have to close the portal again quickly for your own protection.
I am a 1260 Infinity II Gel Permeation Chromatograph from Agilent. In short: I am the GPC. What they call me is all the same to a royal machine like me, the important thing is that the full attention is on me. I am something special and only a few universities and highly specialized industrial companies, such as those in the chemical, food or pharmaceutical industries, have machines of the same design.”
What do you do all day? What are you particularly good at?
“What a question… I pump solvents through my circuit 24/7. I can usually handle it very well, but sometimes a solvent is also very aggressive. It is always extremely pure and therefore very expensive. If it doesn’t flow, my servants have to treat me correctly, otherwise my components could be damaged in the worst case. I and my gel columns can be used to analyze certain properties of plastics, adhesives or food additives, for example.”
How does it feel to pass molecules through your column all day long? Isn’t it monotonous?
“If there’s nothing to analyze and the solvent flows through nicely, I’m happy. But I’m really happy when there’s something to do! I then take a prepared vial of sample liquid with my gripper, insert a needle into the sealed vial and draw out the liquid. The molecules then flow through me and I can observe them with my highly sensitive sensory organs. That is extremely fulfilling for me!”
What are these sensory organs?
“One is like an eye and uses a beam of light to measure the number of molecules in the sample solution, i.e. the solvent including the molecules dissolved in it. It can distinguish whether only solvent or sample solution is flowing through it. The other uses the fact that the solvent and the solution have different viscosities, i.e. their viscosities differ.”
And what’s the gel all about?
“The gel is the filter for molecules. Imagine zooming into the gel. Then you would see lots of individual porous spheres with pores of different sizes that can absorb and release the molecules. If a molecule is too large, it simply flows between the spheres.
Once I have calibrated the gel, the detectors and some other system parameters, I can determine the molecular weights and the distribution of the sample molecules.”
Johannes Küfner is your main supervisor. How do the two of you get on?
“Johannes does a pretty good job. But sometimes he forgets who he’s dealing with and refers to me as a ‘care case’. I don’t have any warning lights, so he has to make sure I’m okay. This means that flushing and cleaning agents are pumped through me, otherwise aggressive salts, for example, could build up and damage me. In addition, my power supply must always be guaranteed – even in the event of a power cut. For this purpose, there is a life-sustaining, uninterruptible power supply directly behind me. But Johannes also has to pay attention to my internal values and always tell my software correctly what I should do.”
Do the students also work with you? If so, what exactly do they do and what tasks do they have to solve? Do they sometimes get on your nerves?
“I’m really very sensitive: some of my sensors are highly sensitive. Bouncing around in the room or pressure fluctuations outside in stormy weather are not good, because I record all of that. So I need absolute peace and quiet for my measurements. Under the supervision of my staff, who oversee everything from the complex sample preparation to the equally complex evaluation of the results, students can also come to me. And of course also external companies, for whom my institute then clarifies special issues.”
You work closely with detectors. Do you sometimes have differences of opinion?
“No, they always agree and are a well-coordinated team. The only potential for conflict is that the connections for my left and right brain come from two manufacturers. Although they have the same thread, they are different lengths and must never be mixed up!”
What is your greatest moment of success during an analysis? What demands do you place on yourself?
“I want to deliver clear measurement results. I am particularly proud of the generation of so-called “baseline-separated peaks”. This means that there is a clear separation between the individual measurement peaks and that all molecules are clearly separated according to their size.”
Are there any molecules that you particularly like? Or are they all the same?
“At the moment, my solvent is polar, so I only like polar molecules. If non-polar molecules were added, they would dissolve poorly or not at all and the separation would no longer work. You can think of it like water and oil – they don’t mix because water is polar and oil is non-polar.”
People say you are essential for polymer research. Does that sometimes put you under pressure?
“Yes! It’s not just that, but also the high precision that I have to deliver and the high time and cost expenditure that I incur. For example, if samples are contaminated, my solvent has aged or I haven’t been serviced for a long time, too much noise or even false signals can occur during the measurement – which I can’t do anything about. Then everything has to be done all over again and my operators are annoyed … But they and I have learned to deal with this huge responsibility.
Incidentally, I’m less interested in applications than in basic research – the latter is my specialty! I think on a large scale and analyze new bioplastics for the agricultural and packaging industry, for example.”
Are you happy here at the university? Who are your favorite neighboring machines? Who else would you like to have here with you?
“It’s quite nice here. But a bit more space and peace and quiet would be nice. I like philosophizing about plastics with my neighbouring machines. They are particularly knowledgeable about the permeability of water and oxygen or about molecular bonds and the decomposition of plastics under the influence of temperature and residual moisture. It would be nice if I could soon be joined by a TG analyst.”
It would be better if ..
“… my solvent wasn’t so expensive!”
What advice would you give to a newcomer who wants to be like you?
“My successor in the distant future (because I’ll be here for a few more decades) should definitely be easier to use!”
In conclusion: What is your motto in life?
“Cheers to that! Always drink solvent!”
Thank you very much for the interview!
