Chromatography Forum

Hello all,
I am running an HP5890 with the 7673 autosampler, and I am experiencing several issues with my system. The runs are being controled by chemstation revision A.06.01.

Issue 1, regardless of manual or automatic injection the chemstation window never displays that the system is ready. This prompted, obviously, double checking my entire method; all parameters and hardware appear to be sorted correctly (oven equilibrated, injectors and detectors at temp, etc.). When I manually inject a sample and hit start on the GC the run starts straight away and it ignores the "waiting for ready" alert. However, if I set up an autoinjector sequence the sequence will run, but with a catch: I must select the option to ignore the "waiting for ready" alert before the sequence will run and in between subsequent injections. Rendering the autosampler impossible to use without someone there to help it along. I'm unsure what it could be.

Any experiences with this? Also, the GC is hooked up to an integrator; could that alter the software/hardware communications?

Issue 2, again with the autosampler. I've used our autosampler on both splitless and split injection, this requires the ability to change the amount of sample delivered by the autosampler to the column. When I enter the sequence parameters and change the injection volume there is no change to the physical volume delivered. This is still the case after compensating for viscosity. If you are curious the volume that our autosampler chooses is 0.8ul. This volume is okay for the vast majority of samples run with the autoinjector, but see Issue 1.

Could this be an issue of worn our hardware? The equipment (and software installation) pre dates my employment. I thought it could also boil down to poor alignment of the autosampler. Finally, could reinstalling my Chemstation make a difference?

Thanks for any help, best wishes.

Make sure any "unused" parameters (like a back inlet when you're using the front) are not set for unattainable settings EVEN IF UNSELECTED. For example if a back inlet is set for 50C, even while un-selected, it may not be able to go that low if the oven is like 150C, so it never gets "ready". So in that case set the unused parameter to like 200C, click OK, then go back in and unselect it, then save method. Etc.

Or load up def_gc.M and see if that ever reaches "ready" state, and start from there. 5890 with 7673 is a good system, even with A.06. I think if it reaches ready then it will be OK.

NALI,

CPG advice is excellent and great place to start (have had the same problem on my own.)

The only other comment, you say you are still connected to an integrator, which makes me think the problem is one of communication between integrator and software (or lack thereof.) Is the GC connected to the computer via HPIB? If so, it might be worth it to get an HPIB card for your autosampler controller and run everything off of the PC.

Best regards.

Thanks for the replies all,

CPG was exactly correct. I altered the method to run both signals off of detector A and voila, a ready light!

I ended up taking down our tray and re-installing it to discover a number of missing screws and supports. Once replaced there were no alignment issues.

On this instrument we do all of our data collection and analysis via PC. The integrator has actually never been used to control the autosampler, and I freqently switch it between instruments.

Thanks for the help,
NALI