Chromatography Forum

What would cause a GC program to completely bypass the injector? This is what happened:

Start program
Turret aligns itself
Skips tray/arm alignment
Rinsed syringe with rinse vials
And here's the strange thing: right before the injection, it goes to the waste vial right next to the sample vial slot, rinses with it (as if it was the sample) draws up from the waste vial and injects it!

And then it continues on, still ignoring the injector and tray.

Just observed, on the next sample, it again bypassed the injection...rinsed the syringe...and then this time injected solvent from the rinse vial!

It's not the tray, it's doing the same thing with a functioning tray. No error lights in the injector box.

Almost as if the turret doesn't know how many slots there are...but that doesn't really explain the GC ignoring the injection/tray.

John

Chemwipe,

Couple of things to look at. First, you might have 101 in your sequence file (but I doubt it.) Or, more likely, you have the wrong magnetic insert in your turret. Take the first vial holder from another autosampler that is working with a tray and swap it with the vial holder on the turret in question. Try the experiment again.

Best regards.

Chemwipe,

Couple of things to look at. First, you might have 101 in your sequence file (but I doubt it.) Or, more likely, you have the wrong magnetic insert in your turret. Take the first vial holder from another autosampler that is working with a tray and swap it with the vial holder on the turret in question. Try the experiment again.

Best regards.

AICMM-

Wrong magnetic insert? Do you mean this small magnet in the corner of the bottom of the turret (top of picture)?



Here is a pic of the bottom of the turret:



and here's the bottom of a turret I was going to swap in...



The bottom is a little bit different...but I'm not sure that this is the issue, since the tray is totally being skipped over during the injection process. Do you think this might be more of an electrical or control box problem? Or...?

Let me also state that the original turret and injector were working fine together the day before I started this thread.

Thanks AICMM!

John

Chemwipe,

Hmmmm! Your pictures tell me that I would no longer focus on the turret (unless you tried it and it worked and now I'm brilliant but I don't think that will be the case.) Assuming you checked not vial 101 in the sequence, the next thing I would focus on is the tray control board. Make sure the HPIB cable is screwed down completely and if it is then, with power off, make sure the board is completely seated. Even easier, swap the controller with one that works. (Troubleshooting is the hard part, fixing stuff is easy.)

Hmmm!!!!

Please advise.

AICMM-

After some troubleshooting and trial and error...Turned out to be the control box! Reseated the boards and now everything is peachy...

it worked and now I'm brilliant

Haha!

Thanks!

John