compare two derivatization methods!

[shangyer]

I try to compare two derivatization methods on LCQ. I wanna compare them in the same ionization conditions, like same solvent composition. With loop injection at 50/50 h2o/acn, the background is huge and I got very weak [M+H] signals for both of them. I tuned the ESI source but still no good. All I can got was the signal from the leftover derivatization reagents. I do not wanna use a LC column because these two reagnets have hydrophilic characteristics.
Any thoughts?

[Kostas Petritis]

Even without chromatography, you will still need to do somekind of SPE clean-up, although then you will have to think about recoveries etc. Depending on the ionizability/polarity of your analytes some ion exchange or hillic or mixed columns should do the job.

Also, I do not see any acid in your solvent composition. Have you tried to add some?

[james little]

Probably the reagents are suppressing the ionization of your analytes. I assume you are doing electrospray ionization.

What about using a very short column or even guard column (2 cm) to do some crude chromatography?

[shangyer]

I did add 0.1% acetic acid. I really do not wanna use SPE, which will cause me a lot of other work. A short column maybe is the choice!
Thanks you guys!