Chromatography Forum

Hi peeps,

I'm having some serious difficulty getting our Autosystem up and running to analyse all three trace gases (CO2, CH4 and N2O). I have had it runnng fine in the past but recently we had problems with gas generators blowing up (!) and autosampler needles breaking. These are all now fixed and the problems have started. The same method is being used and the peaks are terrible. The methane is almost unuseable and the other two are not reproducible. I have had to play with attenuations to get the peaks anywhere near useable scales, and this has caused the baseline to drop sharply prior to the N2O peak, meaning it interferes with proper intergration. (BTW the N2O is measured on a ECD and the Ch4/CO2 on an FID with methaniser).

Any help would be greatfully recieved!

Sounds like a leak somewhere.

In a valve, or septum, or column connection. Poor methane peak indicates that the sample path has a leak or partially blocked column.

Air in the carrier flow path hurts the ECD and the methanizer.

Good luck,

Rod

Thanks for the advice. Have leak checked EVERYWHERE and found nothing. Am going to try and find a second column to try and see if that solves anything but not really sure the column is at fault as it was working perfectly a couple of weeks a go.
Any other suggestions would be awesome as I'm willing to try anything now
Cheers

Are your sample vials and caps still the same? Or have you changed suppliers? Has anyone dropped the crimper (if you use one) on the floor?

Thanks for the suggestions but think I've managed to track down the problem. Changed the capillary tubing that was forming the split, repacked the FID and removed a piece of tubing (it was put in place when many different columns were swapped in and out on a regular basis, and students kept damaging the thread on the base of the FID) and it seems to have sorted out the methane peak a treat. Guessing it was a combination of all these, most probably dead space in the tubing and methaniser packing.

Cheers guys

S

Thanks for giving us the end of the story.

Rod