Chromatography Forum

Hello,

Has anyone experience in special steps which can be done to protect sensitive analytes from decomposition during GC? I have to determine two compounds in a reaction mixture, but I found that Compound 1 reacts to cpmpound 2 also in the GC, probably by traces of humidity.....
Help!!!
Thanks in advance
Flower

Flower,

Do you need to keep your sample containers free of water?
Your injection system?
Your manual syringe?


Can you be a little less general and a bit more specific about the nature of the chemistry involved or is it too secret and company related to reveal?

best wishes,

Rod

Hi Rod,

The sample should remain free of water. It's aromatic esters of PCl3 which have occured a cyclisation reaction, more I don't want to say....
I don't know at all about how many water can come into the sample from the injection system. I'm using the Agilent Autosampler on a 6890.

Thanks
Flower

Hi Flower,

Here are some ideas:

You should oven bake your glass vials and transfer pipettes at a temperature over 200°C and store them in a dessicator.

Try to heat your caps and septum in a manner to remove as much water as possible and store in dessicator also.

Once you pierce your vial septum in the autosampler water will begin to enter the vial.

Don't forget to rinse your syringe in an solvent that will remove any trace amounts of water before injections.

If you had an autosampler that flushed your syringe with dry gas like some of Agilent's competitors do, that would be a wonderful technique to have in your situation.

You might want to place your filled vials in a purged dessicator and only place them in the autosampler immediately before they are injected.

best wishes,

Rod
Good luck.