By Anonymous on Tuesday, July 15, 2003 - 06:07 am:
Does anyone have an idea as to how to separate olefins and parrafins (many long chain alkanes) in a mixture, and quantify them? Is this possible by LC?
By Anonymous on Tuesday, July 15, 2003 - 07:48 am:
Bollocks and crap!
By Chris Pohl on Tuesday, July 15, 2003 - 12:36 pm:
Although this is possible by reversed phase, the long chain alkanes can only be detected using a refractive index detector which is not compatible with the gradient (which you will need if you have a complex mixture). Silver loaded stationary phases will enable a class separation of olefins from alkanes but you won't be able to get both separation and quantitation of individual compounds this way. If I were you, I would use GC.
By Anonymous on Tuesday, July 15, 2003 - 03:57 pm:
How would i use GC to quantify what are olefins and paraffins>?
By Anonymous on Wednesday, July 16, 2003 - 04:12 am:
olefins: unsaturated hydrocarbons
paraffins: saturated hydrocarbons
I've heard about a bromine test/bromine number too, anyone any ideas?
By Anonymous on Wednesday, July 16, 2003 - 08:27 am:
If I remember right there was a LC/GC-combination on the market (10-15 years ago? Philips -- but not sure).First step: class separation, second:GC-individual separation.
Alkanes you can get in steps of 10 units up to Hexacontane (MW 843),about olefin standards I don't know.
Peter
By Anonymous on Sunday, July 20, 2003 - 06:35 pm:
It is possible with a dry silica column and hexane as the mobile phase. The paraffins elute first - unretained, and the olefins elute a bit later, all in a broad peak. This is a simple group separation. If you want to separate them into a multiplicity of peaks, you need reversed-phase, preferentially non-aqueous reversed-phase.