I am a GCMS analyst for an Environmental lab that tests water and soils for volatile organic compounds. I recently changed the block on the back of my archon autosampler and now i have a helium leak on my soil purge needle. However the soil purge needle is not in use and should not be getting any He through it, let alone leaking. I attempted to remove the needle and cap it, but that did not work. we are still seeing a leak somewhere in the unit. any ideas on how this may be fixed?

Could you give us a little more detail about the method you are using, and anything else that might have changed?

i am using method 8260B, but i actually found the problem lastnight before going home. When i had replaced the block on the back of the instrument i must have missed an o-ring on one of the valves. so the problem is fixed now.

Glad to hear that you were able to solve the problem. Visit us again whenever you have questions.

In a related query, I am having trouble with carryover on soils with my Archon. The water method does not carryover. I can up the number of rinses on the water method, but not for soils. Any ideas? Possible helium rinse leak, but all flows seem fine.