Hey #TeamMassSpec, I'm having issues with a contaminant ion @ 248.9 m/z in -ve ion mode when running 90% ACN 10 mM AmOAc at pH 9. Found a thread on research gate suggesting it comes from the ACN but have tried two brands now with no joy. Has anyone else had this problem?
Research gate link: https://researchgate.net/post/What-is-this-contaminant-with-m-z-2489718
ACN brands tried: Fisher Sci Optima, Supelco LiChroSolv. LiChroSolv has a lot less of it than Fisher Sci.
