Chromatography Forum

Hi all,

Can someone help to answer that can alkaline solution can be inject into gcfid/ms?If inject, the sodium hydroxide will stain at the liner. how to overcome it? My method is osha pv2016. I using hp5ms for gcms

Thanks
Seet

I wouldn't do it at all. I don't really like injecting water into my systems. I feel like you're asking for all kinds of trouble if you do this. Perhaps a simple extraction of the caustic solution with an organic solvent will get what you want from the sample?

I just looked at the summary of the method and I wouldn't do it this way. I understand it all the way until the "inject the caustic/methanol mixture" into the GC. Once you're sure the amine is all in the neutral form in the caustic, my opinion is that it would be best to extract it into a more GC friendly solvent for analysis.

Maybe the method works but the thought of injecting a methanol/caustic solution into my GC would never cross my mind.

Most government methods never take into account column lifetime, they just assume you will buy new ones often.

Aqueous works somewhat with the FID, but the MS does not like it so much. If you are trying to substitute the MS for the FID you may want to find a different method.

Hi,
I do modified the mixture of methanol:water to only methanol alone bcos I know ms does not like water. But the difficult part is that after dissolve in methanol need to mix with alkaline, it will stain the naoh on the liner, which will cause a cost for us. It is very hard to get rid of it. I do try to soak with chromic acid, dilute acid to neutralized the naoh, but still does work.

Thanks
Seet