Purification Problem: Amine-pyrimidine

[usuchrom]

Hello,
I have problems when I isolute amine-pyrimidine compounds.
I use a C18 column (Gemini) with some mobile phases:
- Acid: 0,1% Formic Acid with a mixture of MeCN-MeOH
- Basic: 65mM Amonium Bicarbonate or 25 mM Amonium Acetate with a mixture of MeCN-MeOH.
if I use an acid phase, that compounds had formylated
if I use a basic phase, we have lost of amount, and we think that the product breaks down.

I don`t know if I have to use an other column (like a NH2) or another mobile phase with a high pH like NaOH or similar.
What do you think about this problem?

Thanks a lot

[tom jupille]

What about a relatively low pH buffer with no formic acid (phosphate perhaps?)

[usuchrom]

Thanks Tom, I'll try to probe it.

[usuchrom]

Hello,
I read about phosphate buffers and I have found that is a non-volatile buffer and that is a problem for LC-MS. What do you think about ammonium formate as a buffer?

[tom jupille]

I read about phosphate buffers and I have found that is a non-volatile buffer and that is a problem for LC-MS.

And I was supposed to read your mind and know that you were doing LC-MS?

What do you think about ammonium formate as a buffer?

No problem so long as you use it at a appropriate pH.