Manual Inject using HP 6890 and Chemstation

[usdachemstation]

Hi all,

My lab recently pulled out an old 6890 that is linked to an old (that's the theme here) Windows computer with Chemstation revision A.07.01. I've redone the method and sequence tables, but I can't find a manual anywhere online/hard copy. I'm trying to get the GC to take a manual injection with the sequence and method that I've set up, but when I start the run and do an injection, it says "Waiting for Injection." Does anyone know where on the A.07.01 interface there is a button to tell it to recognize the injection?

In another issue, the inlet flow rate is set to 10 mL/min on the Chemstation. When I apply that method, the GC sets itself to 68.7 mL/min (they are connected and working fine, it just takes this really high number). I can reset the GC flow rate manually and the Chemstation doesn't object, but does anyone know why this is happening?

If anyone can answer either question it'd be much appreciated.

Thanks,
Aaron

[rb6banjo]

When you edit the entire method in the Chemstation, do you have it selected as manual injection and not the autosampler? In the D and E versions, it appears as about the 3rd or 4th window into the "Edit Entire Method" sequence.

Make sure that you make all edits on the computer and then download them to the GC. The bidirectional communication can drive you crazy if you don't do it that way. Generally, you set the inlet pressure to what you want it it will calculate the flows according. At least that's what the D and E versions do.

Good luck!

[KM-USA]

We have two GC systems running A.06 and some newer ones.

Under Instrument, first choice is to Select the Sampling System, choose manual injection. Then save method, choose Run Sequence. When the monitor states "waiting for injection", inject and press Start on the GC keyboard itself.

[Peter Apps]

Hi all,

My lab recently pulled out an old 6890 that is linked to an old (that's the theme here) Windows computer with Chemstation revision A.07.01. I've redone the method and sequence tables, but I can't find a manual anywhere online/hard copy. I'm trying to get the GC to take a manual injection with the sequence and method that I've set up, but when I start the run and do an injection, it says "Waiting for Injection." Does anyone know where on the A.07.01 interface there is a button to tell it to recognize the injection?

In another issue, the inlet flow rate is set to 10 mL/min on the Chemstation. When I apply that method, the GC sets itself to 68.7 mL/min (they are connected and working fine, it just takes this really high number). I can reset the GC flow rate manually and the Chemstation doesn't object, but does anyone know why this is happening?

If anyone can answer either question it'd be much appreciated.

Thanks,
Aaron

Hi Aaron

Just in case; unlike Varian/Brukers an Agilent GC has no way of knowing that you have poked a syringe into the inlet. You have to press a start button on the front panel in synchrony with the injection.

Peter

[GasMan]

First, a little more information would be usefull. What type of inlet, what column and flow rates are you trying to use. At first guess, I would assume that you are using a capillary inlet and capillary column. With a capillary inlet you have to understand that the inlet flow rate is NOT the column flow rate. It is the sum of the column flow rate, column flow x the split ratio plus the septum purge flow. The total inlet flow can not be set, it is calculated by the 6890 from the parameters mentioned above.

Gasman

[dhdh]

Hi all,

My lab recently pulled out an old 6890 that is linked to an old (that's the theme here) Windows computer with Chemstation revision A.07.01. I've redone the method and sequence tables, but I can't find a manual anywhere online/hard copy. I'm trying to get the GC to take a manual injection with the sequence and method that I've set up, but when I start the run and do an injection, it says "Waiting for Injection." Does anyone know where on the A.07.01 interface there is a button to tell it to recognize the injection?

In another issue, the inlet flow rate is set to 10 mL/min on the Chemstation. When I apply that method, the GC sets itself to 68.7 mL/min (they are connected and working fine, it just takes this really high number). I can reset the GC flow rate manually and the Chemstation doesn't object, but does anyone know why this is happening?

If anyone can answer either question it'd be much appreciated.

Thanks,
Aaron

Try this. When the PC and GC are ready for an injection (after the method is set-up and the run has a File name entered), then go to the GC control panel. There's a "Prep Run" button between the Stop and Start buttons. When ready to inject, press the Prep Run button. I think it blinks for a few seconds, then when it's ready, go ahead and make the manual injection and hit the Start button on the GC panel.

(added info - before pressing the Prep Run button on the GC, I think you have to click on the "Start Run" or whatever icon on the ChemStation window on the PC)

Try it without the sequence, just a single blank solvent injection or standard solution.
If that doesn't work, there may be 1 or 2 other things to look at...I'm going from memory so may have left something out. DH

[usdachemstation]

Hi all,

Thanks so much for your help, the injection recognition problem is solved, but the total flow rate is still way over where it should be. Each column (they're Porapak Q 6 foot) has 25 mL/min, the ECD has a makeup flow of 5 mL/min, and the overall flow is still at 81 mL/min despite the fact that the column + makeup flows only add to 55. I get the error message CCER C1wwNR P5 E1;EN when I boot up the sequence because of the pressure discrepancy, but I don't see where that is. Any ideas?

Thanks,
Aaron

[GasMan]

What are you using to control the flow in your packed columns? What ever it is, check that you have the correct carrier gas type assigned to it. If for example, if you are using helium as carrier gas and the EPC module is set to nitrogen, you will get the wrong flow indicated.

Gasman

[Bigbear]

Make sure you have only one column configured per injector. 1701 software sometimes sets another column when you're not looking.