H2 detection using Hayesep Q column

[patelnk]

Hello,
Can I detect ppm level H2 using Haysep Q column with TCD detecter?
Thanks,

[chromatographer1]

Yes you can, if you have the proper sampling system and detector, and use a micropacked column. You can use a Carbopack or Carboxen micropacked column as well. Almost any of the porous polymers will work, Chromosorb 100 series or the Porapaks, as well as any of the Hayesep polymers.

But to separate helium from hydrogen will require about 6-9 meters of a 1mm ID column.

You will also need to inject a large volume of sample to get down to a single digit ppm level.

For example, this was done for propane analysis almost 20 years ago at a range of 0-100 ppm with a THERMISTOR bead detector.

Using a pHID or DID will give you much lower levels of measurement.

Contact: Valco, Gow-Mac, Advanced Industrial Chemistry Corporation, or SRI among the many vendors out there.

best wishes,

Rod

[AICMM]

Patelnk,

Many things missing from your post so we can only answer based on what we know. Shimadzu has a web note using a Porapak Q (which others say is similar to the Hayesep Q) at -70 C. Using plain old Hayesep Q would be tough since air is quick eluter but hydrogen is very small and will probably still come out first. Tough separation with a Q. Much better, if you have the money, to get a sieve or some other packing.

Second, you will get more sensitivity to hydrogen if you use nitrogen or argon as the carrier but I suspect you will still have a very, very difficult time getting below 10 ppm. If you are using helium as carrier, no way you will get low ppm levels. Much better to use a discharge detector (or RGD if H2 is the only analyte, although this is an expensive option) since this will certainly get you to low ppm for hydrogen. As noted by Rod, Gow Mac, SRI, Valco, and Advanced Industrial Chemistry all offer discharge detectors which should be able to do low ppm H2 levels. Do you want to run this on an instrument you already have?

Best regards.

[chromatographer1]

With helium carrier you might be able to see 100 ppm of hydrogen with the proper MS 5A micropacked column with a 250µL injection.

The use of nitrogen carrier is critical with a TCD and you must use a column what will separate H2 from He or you may get coelution and confusion of the peaks.

A 3 meter 1/16" OD Carboxen 1004 80/100 mesh 1.25mm ID column would be a good choice for such a separation and you might be able to inject as much as 1mL.

good luck,

Rodney George
Senior Research and Development Scientist
Gas Separations Research
Supelco
595 North Harrison Road
Bellefonte, PA 16823

814-359-5737 voice
814-359-5459 fax
rodney.george@sial.com