Removal of P&T Unit

[rb6banjo]

I have an Agilent 6890+5973N GCMS system that is interfaced with a Tekmar P&T system (autosampler). The transfer line from the P&T unit is spliced into the gas supply line of a split-splitless inlet on the GC. The P&T unit has been nothing but trouble for the past 3 years and I'm tired of it. I would like to disconnect the unit and transform the GCMS system back to a manual injection system.

To remove the P&T unit, is it as simple as taking out the transfer line and connecting the 2 swagelok fittings (1/16") together via a union to establish carrier gas to the injector? It's not clear to me that there is any flow to the inlet of the GC that is supplied by the P&T unit. Anyone else out there ever done this?

[dblux_]

I have an Agilent 6890+5973N GCMS system that is interfaced with a Tekmar P&T system (autosampler).

The transfer line you want to remove comes from a concentrator.

To remove the P&T unit, is it as simple as taking out the transfer line and connecting the 2 swagelok fittings (1/16") together via a union to establish carrier gas to the injector?

Yes. Additionaly you will have to make changes in GC software, ie. change the sample source from P&T to ALS or manual.

It's not clear to me that there is any flow to the inlet of the GC that is supplied by the P&T unit. Anyone else out there ever done this?

The whole stream of gas in desorption stage comes from GC and gets back from the trap to GC inlet.

[Bigbear]

Yes all you need is a union to connect the lines.
What type of trouble have you had with the P&T? Is it really the P&T. or the water in your MS giving you issues?

[rb6banjo]

The darned thing thinks it drops vials. It doesn't actually, it just thinks it does. I've never once come in and found that there was a vial laying in the tray or one jammed down on the tray because it missed the hole.

I've had the service rep in twice and it always "seems" to be behaving when he leaves but shortly thereafter, it starts failing again. It's very frustrating when you set up 30 samples to run over the weekend, only to come in on Monday and find that it only got through 6 of them! It doesn't get enough action in our lab to warrant messing with it anymore. We certainly can't keep throwing money into service calls that don't seem to fix the problem.

[Bigbear]

Aquatek 50?

[rb6banjo]

Nope. Tekmar Solatek 72. It's got some age on it but it's never run nonstop. A large part of any given year, it would just sit there.

[Bigbear]

Sorry to hear! We have an AquaTek 70 which never has done anything odd by it's self. We have caused it to bend needles when we put the trays in backwards!

[rb6banjo]

The last time the service guy was here, I watched him force the thing to move vials (tray 1/2 full) from one place in the tray to another and back again without failure. After he left, it worked well for about 2 weeks and then the "dropped vial" error message started again. Gremlins.....................

[Johnny Rod]

How does it know it's dropped on? Is there a switch in the grabber bit somewhere? You could short it out or tape over it or something like that. Depends on the risk of making an injection if there really has been a vial dropped.

[rb6banjo]

I'm not sure about that one. I checked the manual and it's not clear. It's ok. I'm happier to just have another reliable, stand-alone GCMS system that I can use. As it was, it just sat and sucked helium most of the year.