Chromatography Forum

Has anyone out there in chromforum-land used a 7820A GC and 7697A Headspace? I am having my company upgrade from a HP5890 GC with Tekmar Headspace to this newer model. But, I am concerned that the newer model cannot be front panel controlled, and I have never heard of this model #.

So, I would appreciate any advice on this model #; for example, watch out for ___________, make sure that _____________, absolutely loved it, wouldn't have it in my lab again, etc.

Thank you ver much (in advance) for your advice.

Has anyone out there in chromforum-land used a 7820A GC and 7697A Headspace? I am having my company upgrade from a HP5890 GC with Tekmar Headspace to this newer model. But, I am concerned that the newer model cannot be front panel controlled, and I have never heard of this model #.

So, I would appreciate any advice on this model #; for example, watch out for ___________, make sure that _____________, absolutely loved it, wouldn't have it in my lab again, etc.

Thank you ver much (in advance) for your advice.

I am using a 7820 with an Agilent G1888 headspace sampler with Chemstation with the headspace option.

The 7820 is a smaller and cheaper that a 7890. While you can't control a 7820 from the front panel, Agilent supplies a virtual front panel that you install on the PC.

In general it works OK... I had the engineer plumb it so all the carrier comes into the 7820 inlet through the HS transfer line and it is controlled by the EPC on the 7820 not the Headspace... but that is a non standard configuration with the 7820.

- Karen

Thank you for responding to my post. I was afraid that no one would lend any advice.

Eventhough the 7820A is a cheaper verson of the 7890, does it hold up to use? Is it like a cheap car that tends to break down?

I am having our 7820A configured with 2 FID, one for headspace and one for autoinjector (all controlled by chemstation). My theory is that this will make the GC more versatile as I develop a variety of methods for our products. I hope my theory is correct or this GC will be a very expensive boat anchor.

Thank you for responding to my post. I was afraid that no one would lend any advice.

Eventhough the 7820A is a cheaper verson of the 7890, does it hold up to use? Is it like a cheap car that tends to break down?

Ours has been used every day teh last 2 years without an issue.

I am having our 7820A configured with 2 FID, one for headspace and one for autoinjector (all controlled by chemstation).

Why 2 FIDs? Do you intend to always keep 2 columns on the system?

If you think at some you might need to split a single injection onto 2 different columns, then 2 FIDs could be needed.

Two columns in separate injection ports connected to 2 separate detectors, means you will need to keep carrier flowing through the column you are not using, or you would likely fry it. You can do that of course, but I would just move the columns between injectors and use the same FID. For flexibility I would prefer a different type for a 2nd detector if there a chance you would need one. At my last job I had my GCs configured with a FID and and ECD (for halogenated compounds) and at different times used both. Also with 2 different detectors types you can split he column effluent between them to see different analyte classes or get rid of/minimize interferences for some compounds.

- Karen

That depends what sort of work you're doing and how much your lab changes things. Here for example we change columns about once in a blue moon, and some instruments stay the same for ever because they only really run one method and always need to be available.

We've got 6890, 7820 and 7890 now. The 7820 is fine, Openlab has fewer features than it does for the 6890/7890 e.g. columns are flow controlled only, no constant pressure option (who knows why), also can't adjust septum purge in purged-packed inlet (some gas just falls out, it's not controlled, just total and column flows), stuff like that. I seem to remember that the 7890 is only a bit more in cost.