GCMS- Tekmar 3000 dual concentrator. Naphthalene recoveries

[Kel885]

I have a dual concentrator system. The naphthalene recoveries are off. It reads high on concentrator 1, but low on concentrator 2. The 6- port valves and sparge mounts have been cleaned, I replaced the sparge vessels, and the tubing has been replaced. I also changed the traps on both concentrators. A new calibration curve was also run. What else could be the problem?

Thanks for any input!

[James_Ball]

Do you know if the flow and temperatures of both concentrators are the same?

Possibly try increasing the transfer line temperature of the Low concentrator 5-10C and see if that makes a difference. Also if you have heater jackets for the sparge tubes you could set them to 40C and make sure there are no temperature differences between the sparge tubes due to drafts. A HVAC duct hitting one sparge tube and cooling it could reduce the purgeability of Naphthalene.