Ion chromatography-mass spectrometry

[Christian Fernandes]

I work with alendronate (an ionic drug) and I am using ion chromatography (anion exchange) coupled to ESI/MS.
The problem is that the sensitivity is poor because I use a buffer as mobile phase what decreases the signal to noise ratio.
Any suggestion to increase the sensitivity?

Regards.

Christian

[MG]

I guess you could try HILIC instead of ion exchange. What buffer are you using?

[Christian Fernandes]

I am using formate buffer (with amonium hydroxide).

[Christian Fernandes]

Dear MG,

I do not know if alendronate interacts with normal phase columns (cyano, amino, etc).
I can try to use a high percentage of organic solvent in anion exchange. What do you think about?

Christian

[Christian Fernandes]

Dear MG,

I do not know if alendronate interacts with normal phase columns (cyano, amino, etc).
I can try to use a high percentage of organic solvent in anion exchange. What do you think about?

Christian

[MG]

Well, sometimes HILIC can require large amounts of ammonium formate too. I don't know much about using organic solvents with ion exchange. I guess it can't hurt to try as long as your column can tolerate it. Even 5-10% organic should improve your MS response over 100% aqueous.

If you are going to try HILIC, a silica column might be a better choice than those other two.

[Jeff Brewer]

Dear Christian:

I do not know the answer to your question personally however if you contact my chemist, Jay, I believe he can provide the answer to your question. He can be reached at jg@mp-ic.com. Sorry I couldn't help you personally.

Jeff

[JNF]

Dear Christian,

As discussed before (
http://www.sepsci.com/chromforum/viewto ... lendronate
)
I thought that your problem was thus solved. I do not have any problems with the method. Why did you not use it? did you encounter problems? let me know and bom trabalho
JNF