Chromatography Forum

Hello all:

I am having problem with my Archon type autosampler. It is programmed to take 5ml of sample but it transfers less than 5ml of sample to our purge & trap. I have replaced the filter on top of the syringe and the valve on top of the syringe as well. I get between 3-4 ml of water into the purge & trap. Does anyone have any suggestion what else could be wrong?

Thank you,

Chad

Check solenoid valve on helium manifold or the tubing from helium manifold to water probe. You might notice larger bubble than usual on archon syringe when it's trying draw sample from sample vial. Could be syringe motor drive but not likely.

Dear Koba:

Thank you very much for the suggestions. Replaced the solenoid valve (there was a lot of corrosion) but I still had the same problem. Then noticed a small drop of water coming off of the needle. Replaced the needle and problem was solved. Thanks again.

For future reference there are two other possible places to lose water when being transferred to the sparge tube. The Burkett valve that goes to drain can leak if particulates get caught in it or it wears out, and the one that controls fluid flow to the soil needle can have the same problem. If the soil needle valve leaks you will see water drops at the soil needle when running water samples, if the waste valve is leaking you will see movement of water in the waste line when filling the sparge tube. Also if the waste valve is leaking you will see the volume in the sparge tube slowly decrease as the purge progresses.

Luckily the valves are easy to replace if they ever do leak.

Thank you very much James for your help.