Qtof contaminants at m/z 200 and 270

Question

Hi!

We are using three Agilent Qtof's (6550) and all shows annoying, significant contaminants and the nuisances are usually started to be detected after a gradient hits 50%MeCN until the end. Their m/z values are ~200.2386 and 270.3172 as shown below. Is there any group who has experienced to resolve such an issue? Where are they coming from?

Thank you and be safe!

Best,

Joonseok

ondrej · Answer

Mass 200.2386 is formula C13H19N. It might be an additive used in some polymers - Atmer 163 or something similar. Mass 270.3172 is formula C19H39N - octadecylamin. It is probably also comming from some polymer.

It seems you have them in mobile phase. Try to change different organic solvent - MeOH or different producer of ACN. If the contamination would be still present, try to use different water, buffer, change pipette tips for one of higher quality. It is very difficult to find a source.

One more note: Since you have 6550 - iFunnel QTOF, I would try to use higher fragmentor voltage, about 380V. You may get significantly higher sensitivity.

Qtof contaminants at m/z 200 and 270

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