GCFID flame ignition problem

Discussions about GC and other "gas phase" separation techniques.

5 posts Page 1 of 1
We have a Perkin Elmer Clarus 590 GCFID and although it was supplied two years ago, we are only just using it now. It has manual pneumatics control and so we have to manually adjust for carrier pressure, split flow, hydrogen and airflow for the FID. After adjusting the hydrogen and air flow following the instructions in the manual, the flame will not ignite even though we hear the pop sound upon clicking the ignite button. Our hydrogen flow was set at 30 ml/min and air flow 450 ml/min. Psi values for all gases is set to 90 for Helium (the carrier gas), 40 for Hydrogen and 50 for Air. I have checked to make sure that there no leaks and the FID is heated up to 200 degrees.

According to the manual, you open up the hydrogen flow and immediately after turn on the air flow. we did exactly that, hear the pop sound, but the flame does not ignite. Suggestions will be well appreciated because we have a pile of work we need to run on the instrument and it is getting frustrating.

Thank you.
Flame jet may be clogged , but before proceeding you may try to increase Hydrogen flow to 40 ml / min and decrease Air flow to 100 ml/min.

After ignition , adjust the flow to default values .
Since you're doing it manually, you can't easily adjust the gas flows after it's lit.

If it were me, I'd just adjust the air flow to 300 mL/min and try that. Agilent systems work on a 10:1 Air:H2 flow ratio. A flame detector is likely a flame detector. The high air flow could be blowing out your flame.

The other thing you could do is adjust the air flow to the lowest value that you can get it lit. Once you know that it will light, then you can increase the air flow gradually to find the value that will make your flame as efficient (and quiet) as possible without blowing it out.

If none of that works. Cleaning the jet might be your option.
Marye,

As pointed out by rb6banjo, since you have manual flow controllers, it will be difficult to find the proper flows after the flame is lit by trying to adjust the controllers. I would suggest a different approach.

If this is not a shared GC, ie it has its own regulator for air and hydrogen, then put a mark on the air regulator at the current pressure. Then reduce this pressure by 30 - 40% or so and try to re-light the FID. If it lights, then slowly increase the air regulator back up to its original pressure. If it is a shared GC you should consider a regulator for the air pressure directly upstream of this GC and try the same process.

The comments about more hydrogen relative to the air are appropriate BTW and a hotter detector lights easier than a colder detector.

Finally, I would ask, is this being lit by a glow plug and if so, a glow plug permanently attached to the FID detector or one that is hand held like the old PE. Reason I ask is that I have found the solution to Agilent FID's not lighting and was wondering if PE's are configured the same way.

Best regards,
Thanks for all the suggestions in response to my post. I was able to solve the problem. So I found that setting the flow rate of hydrogen to 40ml/min and air to 450ml/min while maintaining the FID temp at 200 degrees, enabled a successful ignition of the FID. After ignition, I increased the FID temp to my required temp for the analysis.
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