Chromatography Forum

Hi everybody,

We have to transfer a method from LC-UV to LCMS (ESI). In the original method there is sulphamic acid and NaOH in the mobile phase (pH2) and a silica column, C18.
My question is about the use of sulphamic acid and NaOH with the detector MS.. I think we need to change them with TFA to get the same pH and similar elution.
What do you think about this?

Thanks in advance for the help,

Have a good day!,

Davide

The TFA could suppress the response. Could try 10 mmolar ammonium formate adjusted to pH 3.5 with formic acid and see if you get adequate retention with a high aqueous content of the mobile phase.