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LC mobile phase
Posted: Tue May 17, 2011 7:24 pm
by lwyyeung
Dear all,
Just a curiosity, I came across a LC run, mobile phase A is 2mM ammoniun acetate (90:10, water:MeOH), and B is MeOH. What is the reason adding MeOH onto mobile phase A?
Please advise.
Re: LC mobile phase
Posted: Tue May 17, 2011 9:34 pm
by JGK
In the olden days before technology advanced and vacuum degasssers became common, the average chromatogapher would never begin gradient elution with 100% aqueous and 100% organic solvents.
Premixing some organic into the aqueous phase dramatically reduces bubble formation when the two phases are mixed and led to much betterchromatograms.
Re: LC mobile phase
Posted: Wed May 18, 2011 6:20 am
by Gaetan Glauser
Another reason is that it will prevent or delay bacterial growth in the A line.
Re: LC mobile phase
Posted: Wed May 18, 2011 10:59 pm
by Kostas Petritis
And let's not forget the "dewetting" problem of reversed phase columns