Chromatography Forum

Hi all

I have been working with sugar acetates on the FID and am able to do monsaccaride aldoses sugar alcohols and disaccarides. I also found a new method to do both ketoses and aldoses together I can try. I've heard a lot of people say it was a pain doing sugars on the GC but it seems fairly simple.

http://pubs.acs.org/doi/abs/10.1021/jf3053862

Anyway the monsaccarides come of at about 200 deg C and the disaccarides at 320. I am wondering if I try a high temperature db-5 column (which can go up to 430-450 deg C) if I can go up to trisaccarides which I assume should come out at arround 400-430 deg C. The question I have is I think the temperature limits on the 5890 FID and inlet are 400 deg C What do I need to do about the septa, liner and gold seal?

Change them more often

Some of the septa I know says rated up to 350 deg C so I am uncertain if I need a special septa. I am not sure about the liners or anything. I am concerned the high temp will quickly destroy the deactivation and such. Also will the 5890 let me take the FID temp a bit passed 400 deg C (to 440 or so) and will it damage anything?

Depending on how much resolution you need it might be worth thinking of a shorter column, thinner film and more gas flow rather than temperature to get the trisacharrides out.

Peter

I don't think I can get any shorter than 30m lactose and maltose are not quite baseline resolved.