By Benjamin on Wednesday, July 28, 2004 - 11:04 am:

Dear Friends,

I have received a request for information on the use of HPLC to fractionate and analyze aromatic hydrocarbons. The idea is to use some sort of column and mobile phase system to separate by groups a complex mixture of aromatic hydrocarbons (one, two, three, etc rings).

If any of you have a good reference on this subject, please reply to analchembe@aol.com.

Thanks for your help.

Benjamin

-------------------------------------------------------------------------------------------------------
By Uwe Neue on Wednesday, July 28, 2004 - 02:43 pm:

The classical way to do this is to use an amino column with hexane or heptane as the mobile phase. An example of such a separation can be found in my book "HPLC Columns" on pages 175-176.

-------------------------------------------------------------------------------------------------------
By Benjamin on Wednesday, July 28, 2004 - 05:11 pm:

Thanks for the information. I have seen the chromatograms you mention. Is there any way to fractionate the aromatics using the same column?, are there any advantages using amino columns over Silica columns?, do you know of a more specific reference?

Thanks,

Benjamin

-------------------------------------------------------------------------------------------------------
By Uwe Neue on Thursday, July 29, 2004 - 04:19 pm:

Silica is not supposed to work for the clean separation by ring size. You can calibrate the system with standards, and then collect the fractions that contain 1, 2, 3, 4 etc rings.

A further fractionation of the fractions is probably done best with an orthogonal technique. Reversed-phase comes to my mind, or simply a silica column in the same mobile phase. I would think that RP will work better, though.

-------------------------------------------------------------------------------------------------------
By Uwe Neue on Thursday, July 29, 2004 - 04:21 pm:

Unfortunately, I do not have a reference handy...

-------------------------------------------------------------------------------------------------------
By Benjamin on Friday, July 30, 2004 - 01:04 pm:

Thanks for your messages. It is also possible that a very efficient SEC column could do some fractionation. I agree with you, an orthogonal system is most likely to do the fractionation.

Thanks.

Benjamin

-------------------------------------------------------------------------------------------------------
By Constantin Sychov on Saturday, July 31, 2004 - 10:21 am:

I think the best way is to do this on hypercrosslinked polystyrene. Separation is several times better than on NH2.
For information you can request new catalog of Purolite, the phase is Chromalite 5HGN.
Or I can give the link - download first pdf in the list on

-------------------------------------------------------------------------------------------------------
By Constantin Sychov on Saturday, July 31, 2004 - 10:22 am:

http://www.anchem.ru/literature/methods/

-------------------------------------------------------------------------------------------------------
By Benjamin on Tuesday, August 3, 2004 - 08:55 am:

Dear Constantin,

Thanks very much for the information. I was not aware of such adsorbent and its versatility.

Benjamin