Chromatography Forum

Hi all.
I have liqud gas sample - mix of propane, butane, dimethylether and 1,1-difluorethane and i need analyse liquid phase. What detector I need (I think about thermal conductivity detector, can I use it?)? Can I use singlecolumn system (with Poropaq Q ) or I need 2column sysnem (polar - nonpolar)? What column I need? Wat injection system better for use (gases are liqud!!)? If you can, tell my what company staff better for use.
Thanks for all.

The only question is whether dimethylether will separate from propane on the Q polymer. I suspect due to the separation of pentane from diethylether that there will be some separation. I would suggest a long column, at least 3m in length if not 4 or 5 meter.

The use of a polyester packed column should separate these two.

You can use FID or TCD as a detector.

There are companies that supply and evaluation chromatography systems for a fee. If this analysis has value for you, then by all means contract a company to furnish you with the proper system. Otherwise spend a few dollars on columns and determine yourself if these separations are possible.

best wishes,

Rod

Thanks alot
Can i use FID detector for determinate fluoroorganic compound ?

The FID will detect the difluoroethane peak, it will not have the sensitivity of propane or butane but dimethylether does not either.

You should have more sensitivity with the FID than with the TCD for most designs.

IF you are more concerned with consistency of response then you should use a TCD perhaps. But why a lower more consistent response would be preferred is unknown to me, not to say you have a good reason

I would use a traditional liquid valve injection system but attend to the pressure and temperature so your sample does not bubble in the sample loop.

If you use a vaporizing pressure regulator you could inject vaporized liquid as a gas.

If Q does not separate dimethylether from propane then you could try the 'T' polymer instead.

best wishes,

Rod