The pH of the solution obtained (containing the diacids) is 2.33, and the method says we need to prepare a buffer solution of ammonium acetate 5mM with a pH=3.3 as 70% of the mobile phase, the rest will be 30% methanol.
There is no danger on the C18 column? because some people said it will not be good for the column if acids get injected.
pH of 3 is no problem for commercial C18 columns, so no problem from your mobile phase. a different pH of injected samples is buffered by your buffer, so no problem from your sample. some columns even withstand pH lower than 3. check the tolerated pH range of your column with the information provided by your manufacturer.
ammonium acetate is a very good volatile ms compatible buffer.
I think there shouldnt be any problem of using ammonium acetate.
But i prefer ammonim formate adjust ph by formic acid. when working ph is 3.3 as AA has a pka 4.8 so we can only work form 3.8 to 5.8 and we need to use acetic acid to adjust ph or else buffer capacity will not be maintained.
Use a solution of tributylamine (~0.10%) and acetic acid (~0.03).
Thank you for your replies...but my point is, since the method is described in an article so I think there should be no problem, however, some researchers commented on the method saying it will PROBABLY affect the C18 column because the molecules contain the carboxylic function with an acidic pH=2.33 (the 70% mobile phase pH=3.3 which is ammonium acetate 5mM), so I want to be SURE that the method is safe for the column.
pH of 3 is no problem for commercial C18 columns, so no problem from your mobile phase. a different pH of injected samples is buffered by your buffer, so no problem from your sample. some columns even withstand pH lower than 3. check the tolerated pH range of your column with the information provided by your manufacturer.
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