Does anyone know the pH range that dimethyloctylamine can be used in? Is it compatable with LC-MS?
I am having a bad tailing problem with one of my first eluting peaks. My injection volume is 20 ul & the buffer I use now is 25 mM ammonium acetate at pH 6. TEA doesn't help, washing the column with a strong solvent doesn't help. Any suggestions?

DMOA can be used at pH<7 or better pH<6, otherwhise t is not water-soluble. Once, I used it with good results for peaks with bad tailing, but that was 10 years ago. I think you can solve the problem by changing the column.
Have you tried another column (low metal silica, like Phenomenex Luna or Waters Symmetry)?

You can fix the solubility problem of dimethyloctylamine in water by adding some organic solvent to your buffer. However, I doubt that it is good for LC/MS. What happens to your peak when you change the pH?

In my experience, dimethyloctylamine does not work significantly better than triethylamine. Furthermore, it is not as soluble. I like Anonymous' idea of trying a different column. If I knew what the compound was it would be easier to suggest solutions.

Thanks for the responses. I used a Luna column a while ago, but choose the Zorbax SB for a specific separation problem. Now that I look back at the data, the tailing is much improved on the Luna (1 compared to 3!) If I can maintain the separation with the Luna,I'll be all set!