Chromatography Forum

For hydrogen determination, I am using two columns 1. Plot Q polymer column and 2. molecular sieve column as established methods by our laboratory. But I need to know why we are using two columns? Though we do not have any problem for determination methods.
It will be appreciated if someone clarify me.
Thank you

Ya got me on that one. Not much will interfere with H2 on a mol-sieve. Does your analysis really only go after H2? Perhaps when the procedure was developed, there was more to it than just H2? I've seen legacy analyses like this get carried through. A generation or 2 of scientists in the lab and nobody remembers why we do what we do.

You need to tell us exactly what you are trying to measure. What other gases are present in your sample other than hydrogen, that will then tell you why you may need two columns.

Gasman

Thanks both of you.
I am measuring only hydrogen now by using these two columns.
Want to know the function of these columns, why we use two column?

Thanks both of you.
I am measuring only hydrogen now by using these two columns.
Want to know the function of these columns, why we use two column?

Please read carefully what GasMan wrote: "What other gases are present in your sample other than hydrogen, that will then tell you why you may need two columns. "

If it is only hydrogen then you don't need to measure it. It's concentration would be 100%.

It seems to me that what you are getting at would be explained by looking at some application notes for the columns of interest. Check out www.restek.com or www.agilent.com, look up some app notes for each of your columns and you'll see what they can do for you. Based on your sample mixture (per what GasMan was talking about), it the app notes will likely tell you why you need 2 columns.