How do I know it is time to change my carrier gas trap?

[zimanli]

I saw the answer some where, and attemped searching for it, but failed.

I have a lot of water in my system. Except I injected some water, I also changed a carrier gas tank and a universal He carrier gas trap. This trap was more than one year old. And I found that a H2O trap (bought the same time, but not the same one) which is also a year old changed color from dark blue to tan even though I newly opened it. So I am suspecious that the universal trap I am using is spent also.

How to check if the trap is good or not? HOw do I know if water is from my GC/MS or from the carrier gas?

[Peter Apps]

Hi Ziman

Remove the caolumn from the MS interface and cap the connection. Pump down. If the water is less, it was coming fror the carrier gas. Keep the MS pumping with the source and analyser hot and watch the water levels with time over several hours. If they were initially high and get lower they were could be from the gas or from the MS. If they stay high you have a leak (but you checked that already). When the water levels have dropped, reconnect ehc olumn, if they go back up the gas is confirmed as the source and you need to change both the tank and the trap. If the water stays down the problem is solved.

Peter