Chromatography Forum

Hi Everybody!

Im currently developing a GC-MS method for volatile amines using the CP-Volamine column.
We plan to analyze water samples and to measure the amounts of amines.

I have question regarding the pH influence on the analysis. At low pH the amines will be in ionized form. How will this affect the results?
Will the ionized amines enter the GC-MS and I will be able to quantify them??
Or do I need to adjust the pH to have the amines in neutral form??


Thanks in advance

Ions or ionized molecules do not chromatograph well. They usually remain in the injector port and since most have very little volatility, migrate very little down a GC column.

It is different in ion chromatography, LC, and TLC. I would prefer to analyze amines in matrices by other techniques than GC if given a choice or an opportunity.

Place the amines in neutral form, and beware that amines can change their structure and can combine when in strongly basic solutions.

Good luck,

Rod

GC-MS is the only option for us.

There is an application note on the agilent website on volatile amines
http://www.chem.agilent.com/Library/app ... -01613.pdf

It's this application note that I will use. But the pH influence worries me (they don't mention anything about this)

I will test analyzing my amine standards at different pH and see how this affects the results.

There are many techniques out there for volatile amines in water. They generally seem to involve making the water basic and then extracting with solvent, SPME, some other sorbent or sample the headspace above the water. Is there a particular published method that you are working from or are seeking to modify?

Minotauro,

Can you not simply analyze your water samples by headspace? Normally it should work for MMA/DMA/TMA and other light amines and you should be able to achieve ppm levels. I think that with this technique the ph will not have an influence on your results.

Actually it will have a great influence.

Rod