Smaller areas using hydrogen carrier compared to helium.

[Peter Apps]

I just managed to miss dual FIDs and packed columns - I cut my chromatographic teeth on in-house glass capillaries in a Varian 1400 with a home-made thermal desorb unit, which kind of set the trend for subsequent developments !

I have just dug out an old paper from the late seventies on chemical signals, for a review that I am putting together - they used a 500 foot metal capillary column that took eleven hours to elute a C24 ester as a peak about 10 minutes wide ! I can now do that on a 30 m silica column in a bit more than an hour and the peak is 10s wide. That really is progress.

Peter

[chromatographer1]

Heavens ! What temperature do you START your analysis for that C24 ester (lignoceric? acid, gosh my memory is failing faster and faster anymore) I eluted it in less than 12 minutes thirty years ago when testing it for release for sale at Sigma Chemical, now the C28 ester did take longer and the C29 we had then wasn't a straight chain acid but who knew?

best wishes,

Rod

[Peter Apps]

Hi Rod

I usually start at 40 or 50 C and program at 5C/min - the problem is all the interesting things that come out before the heavy esters, squalene, cholesterol and so on - the heavy molecules are probably (but not certainly) just acting as fixatives for the signalling compounds among the lighter molecules.

Peter

[chromatographer1]

Well that explains a lot.

You certainly have applications that few in the world can imagine.

So glad that me is not thee !

Rod

[Yama001]

Peter does work with some fascinating stuff. I love it when you two get going; the advice as well as the stories are fantastic.

[Peter Apps]

Just think of it as doing residue determinations without having target compounds, or taints and off-flavours without being able to use GC-sniffing.

Peter

[AICMM]

pdelt,

What type of GC? 5890, 6890, or 7890, Varian 3400, 3800? Etc...

Best regards,

AICMM

[DR]

You guys are really showing your age today...

[Peter Apps]

DR you are a scholar and a gentleman !

Peter