Chromatography Forum

Hi, I am trying to measure the purity of Helium (almost 99.99% v) using GC - TCD with Argon as carrier gas, Molsieve 5 A column. Trying to make a calibration curve. Can anyone help me to understand reasons for comparatively reduced responses, eventhough the big thermal conductivity differences between Ar and He? How to improve it?

Why are you trying to perform related substances on gases which are a 'processing aid'? If you have manufacturing problems why not just use a higher purity gas (like 99.9995%)?

As I recall, gas chemists would take the nanoliter injector out of the loop and inject directly from the gas bag 1 or 10 mL. Ask Maxxum Analytics for a method!

Takes a special purged sampling valve. You don't really analyze the He; you analyze for the impurities. You'll never get there with a TCD; you need to see low ppm levels of Ar, O2, CO2, N2, etc. Use He as your carrier so that you eliminate the He peak.

Hello my friends,

This is my first post. I have a few questions.

I want to probe emissions at high temperature (1400-1900K).
As you know, it is important to sample carefully because it is very likely that radicals decompose immediately at this range of temperature. I have looked at the techniques for gas sampling; however, I do not know which one is proper for using yet. Could you please recommend the appropriate technique?

I think it might be necessary to cool down radicals immediately after probing in order to prevent radical degradation. Do you think using aerodynamic nozzle is a good choice? Do you have any suggestion for this?

Thanks in advance for your help. I am waiting for your response.