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- Posts: 199
- Joined: Mon Sep 22, 2008 7:50 pm
We're still using an old Varian 3400 with the on-board integrator (obdh - on board data handling per Varian) for one app. Using a TCD and PLOT column for ethylene/propylene in solids by headspace.
It's consistently missing the propylene peak. I think the baseline drift from the temperature ramp is fooling the integrator and it's missing the start of the peak. It isn't putting the start tick on this peak.
We were using FID for this, but had to change to TCD as the GC needs to be moved to an area that doesn't allow for hydrogen. The "new" air peak from the TCD was an issue, so we had to go from isothermal to temp ramp to get the separation from the air. Hence the baseline drift.
Looked at the peak width, it's right where it needs to be. Turned the sensitivity (S/N in IBDH) from 5 to 3 - just got more peaks - didn't help. Don't see much else in IBDH.
Fallback is to A/D into EZChrom. May end up there. I could fix it in 2 minutes with EZChrom.
It's consistently missing the propylene peak. I think the baseline drift from the temperature ramp is fooling the integrator and it's missing the start of the peak. It isn't putting the start tick on this peak.
We were using FID for this, but had to change to TCD as the GC needs to be moved to an area that doesn't allow for hydrogen. The "new" air peak from the TCD was an issue, so we had to go from isothermal to temp ramp to get the separation from the air. Hence the baseline drift.
Looked at the peak width, it's right where it needs to be. Turned the sensitivity (S/N in IBDH) from 5 to 3 - just got more peaks - didn't help. Don't see much else in IBDH.
Fallback is to A/D into EZChrom. May end up there. I could fix it in 2 minutes with EZChrom.
