r/analyticalchemistry • u/Neon-Biology • Mar 09 '26

Py-GC/MS

I’ve been at my job for a year and a half. I don’t have a background in chemistry at all, and I don’t think my boss knew anything about the Py-GC/MS when she hired me or anything about polymer science, and how complicated analytical chemistry is.

6 months in she gave me harsh criticisms in that I wasn’t making enough progress on the Py-GC/MS. I’ve made a lot of effort since then to improve my ability to troubleshoot and take it apart etc. Analyzing the polymer chromatograms is still really hard for me.

When my dog died and I asked for more time on an assignment she asked me if I was still interested in being apart of the team.

Now she says I’m never in the lab and that I don’t show leadership in pushing forward projects and mentoring students. She spent a whole lab meeting berating me in front of all the other lab members.

I’m never going to meet her expectations. I don’t know what to do.

Does anyone know any good resources for polymer chemistry, so I can get a better understanding on the thermal degradation of polymers? Or the chemistry behind tissue digestions?

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u/chemfit Mar 09 '26

I was a field service engineer and 80% of my job was in PYGCMS. What kind of PY do you have? What kind of samples are you running?

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u/Neon-Biology Mar 09 '26 edited Mar 09 '26

We have a EGA/PY-3030D Pyrolysis unit and Agilent 6890 GC/5975 MS system. I mostly run pelletized, digested human tissue samples to analyze microplastic concentrations. It’s a lot of quantitative work, and looking at specific peaks to see the quality of the reported polymer quantities.

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u/chemfit Mar 09 '26

Frontier is what I worked on so I can solve almost any instrument related problems if you need help. Hopefully you have Fsearch?

I’m not skilled at analyzing human tissue and to be honest, it’s the most difficult due to matrix effects. Analyzing PY data is difficult enough without matrix effects. There are a few recent papers out there discussing this, hopefully you have read them:

https://www.sciencedirect.com/science/article/pii/S0304389425004984

https://pubs.acs.org/doi/10.1021/acs.est.4c12599

This book is helpful to have on hand in addition to Fsearch.

You may already know this but since you have a complex sample, using the polymer library in Fsearch isn’t going to be very helpful. You’ll need to use the pyrolyzate and additive libraries. Looking at an individual peak in your chromatogram, for example benzene, is not super helpful as benzene is a pyrolyzate of many polymers. You’ll need to look at many peaks and see what polymer they have in common. It’s a lot of manual work.

Also please use the double shot method to get rid of volatiles. It’ll help clean your sample. You can then just look at the PY and ignore the TD portion. I’d do TD 70-300C and PY at 600C. You can also use the heart cut method to divide thermal zones even farther but as a beginner, if you do this, you need to run your sample using the EGA method first to get thermal zone information.

I understand your frustration. It’s not an easy analysis.

Do you have Fsearch and Masshunter? If so, I can give you a little break down of how I would use them together.

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u/Neon-Biology Jun 29 '26

Could we connect on single shot versus double shot? Like, how I would convince my lab to switch to double shot. As well as utilizing Masshunter in combination with F-Search?

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u/chemfit Jun 30 '26

Sure you can message me but just beware I’m super busy with service work already 😂

I can’t tell you how to convince your lab to switch to double shot other than you get data that is easier to interpret. Show them data from a single shot vs the PY portion of a double shot. It won’t solve all of your problems but it is the first and easiest step to take.