Change in GC (IRMS) chromatogram after maintenance

[Peter Apps]

Hi Alice

When you did the earlier maintenance, and the recent column change, did you change the gold seal at the bottom of the inlet ? Tailing with a brand new column is very likely to be dirt somewhere in the inlet.

Also, when you installed the new column did you trim a few cm off the end after you threaded it though the ferrules ?

Peter

[UBC Forestry SIF]

Hi Peter

I was going to inspect the gold seal, but the reducing nut was on so tight I was unable to take the entire assembly out. I will try again though.

Yes, I did trim some segment off the column after it was threaded through. I could see some of the graphite from the ferrule go into the column. Thanks.

Alice

[Peter Apps]

Hi Alice

If the nut is on that tight it has probably never been removed, and you have 4 years of accumulated gunk sitting inthe bottom of the inlet - that would be enough to account for the problems.

Peter