Newby 6890 GC problems

[laurimc]

I've played around with temperatures and flows and have gotten improved resolution, but my peaks are still more broad and short than I expect. They are fairly symmetrical and the peaks are near where they should be.

What I've done:
-Increased make-up flow from 20cc/min to 30cc/min. Some improvement.
-Decreased oven start temperature from 40C to 30C. Big improvement.
-Increased inlet temperature from 210C to 250C. Big improvement.
-Increased column flow from 32cm/sec to 40cm/sec. Minimal improvement.
-Decreased column flow to 28cm/sec. No improvement.
-Increased purge delay on splitless inlet from 45sec to 90sec. Huge tails!

So I kept the increased make-up flow, the decreased oven start temperature, and the increased inlet temperature. Any more ideas?

Thank you, thank you!

[Bigbear]

Your early temps. may be your problem. We do 552.2 using a dual column setup DB-XLB and DB-35. Both 30M X 0.32.
Our temp ramp is
40 C for 1 min
3C/min to 80
10C/min to 120
20C/min to 200 no hold.

[laurimc]

I played around with the oven program quite a bit and ended up with nice resolution for 90% of my peaks. Now calibrating!

Thanks for all your help everyone!