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UPLC mobile phase with pH above 10

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

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Hi,
I am using a mobile phase A (80% of acetonetrile, 10 mM ammonium formate) and B (50% of acetonitrile, 10 mM ammonium formate). The pH of mobile phase was adjusted to around pH 10 with ammonium hydroxide (need a lot of ammonium hydroxide). the preliminary data looks promising. But I worry about the the amount of ammonium hydroxide there. will it be stable (or evaporated out)? the separation of targets compounds favor high pH and high buffer concentration. Should I use higher salt concentration (15mM) and lower pH (around 9) to minimize the amount of ammonium hydroxide? Thanks for any suggestions?
What about something like triethylamine (pKa = 11) and adjust the pH down with a bit of phosphoric acid? Should be significantly less volatile than ammonia.
-- Tom Jupille
LC Resources / Separation Science Associates
tjupille@lcresources.com
+ 1 (925) 297-5374
2 posts Page 1 of 1

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