Chromatography Forum

I've got the manual on order, next-day shipping, but I'm impatient as hell.

What are some basic settings (kPa) to try for the Hydrogen and Air pressure controllers for the FID on a Shimadzu GC-17A?

And am I missing something, or does the FID on this thing really not have any plumbing for make-up gas?


Thanks in advance.
Mike

Air: 50kPa (approx 500mL/min)
H2: 60kPa (approx 50 mL/min)
Makeup:
N2 75kPa (approx 30 mL/min)
He 80kPa (approx 30 mL/min)

There should be (at least) three gauges under the cover at the back of the GC for H2, air & makeup. The makeup gas should be marked "AUX". If you've only got two, maybe the GC is configured for packed column analysis only. Should still work for capillary, but sensitivity will be down quite a bit.

Air: 50kPa (approx 500mL/min)
H2: 60kPa (approx 50 mL/min)
Makeup:
N2 75kPa (approx 30 mL/min)
He 80kPa (approx 30 mL/min)

There should be (at least) three gauges under the cover at the back of the GC for H2, air & makeup. The makeup gas should be marked "AUX". If you've only got two, maybe the GC is configured for packed column analysis only. Should still work for capillary, but sensitivity will be down quite a bit.

There's an AUX controller, but it's only plumbed to the ECD. The GC was purchased used (and all the documentation & accessories were lost in shipment), so I'm not entirely sure what it is was set up for from the factory (capillary v. packed FID).

If low sensitivity is going to be the only problem with not having make-up, then no worries , because I'm trying to get it to do assay of percent-level hydrocarbon blends.

Those Air/H2 setting seem to be working so far. Thank you very much for your help.

Mike

Yeah its OK to run capillary FID without make up gas for your type of application, you might not see any difference.

Just an update for future searches:

The owner's manual arrived, and it's (obviously) full of useful information. Well worth the prince.

Anyway, the flows that macgyver gave are good starting points.

As for the make-up: I've been using the GC without any make-up gas, and have been getting good results for percent-level mixtures (as aldehyde said I should).

But looking through the manual, it would seem that the make-up gas enters the FID through the same tubing as the make-up gas does. The make-up and hydrogen are presumably mixed up stream.

So, if you need make-up flow, yes Virgina, those two lines of tubing entering the FID are all you get for Air, H2 and Make-up.

For the (rather pricey) Shimadzu fittings to t-things together, they now have a semi-useful online store: U.S. Webstore.


(Digression: On the whole, I quite like the plethora of Shimadzu GC's I've been working with. But the process of identifying and ordering parts is byzantine at best. And the lack of easy ways to adapt from their metric fittings to more common (e.g., Swage-Lok or Valco) and/or English-sized (e.g., 1/16") is a constant annoyance.)