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compare two derivatization methods!
Posted: Tue Jan 31, 2006 4:15 pm
by 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?
Posted: Tue Jan 31, 2006 4:22 pm
by 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?
Posted: Tue Jan 31, 2006 11:40 pm
by 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?
Posted: Wed Feb 01, 2006 4:26 pm
by 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!