Did anybody come across this impurity at around 1800 m/z and knows what it is and how to get rid of it? I guess its a polymer and I was not able to clean it of my system with 1:1:1:1 = H2O:ACN:Isoprop:MeOH.
Thanks in advance.
What is the mass difference here? Are the singly or doubly charged? It could be Tween. Have a look at the MaConDa database for ideas.
https://maconda.bham.ac.uk/browse.php
Are you using an electrospray ion source? In ESI ion source an impurity might come from contamination of the ESI solvents. Have you tried to use a completely different batch of solvents?
Hello all,
thank you very much for your responses. I measured the spectra once again now and found out that the main impurities we see are PEG and Polysiloxane. See attached image. Interestingly, we see PEG in our solvents (Experiment 1, applied manually via Hamilton syringe). If we run these solvents via our LC pump only (Experiment 2, nothing else, no column) , we see both, PEG and Polysiloxan.
We used new LC-MS grade solvents and glass bottles (to prepare ACN:H2O:MeOH:Isoprop=1:1:1:1) and are pretty curious where we got these impurites from (gloves?, glass bottle caps). Do you have a clue where these PEG impurities might come from in our solvents?
Do you maybe also have a clue why the pump is bleeding showing Polysiloxane?
Thank you very much again for your replies.
Looking forward :)
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