Diphenyl Vs. Biphenyl

[rick1112]

Hi
whats the difference in terms of selectivity and resolution between Diphenyl and Biphenyl columns ?

thanks

[mattmullaney]

Hi rick1112,

I'm not sure, but as I recall, Restek introduced the Biphenyl stationary phase quite some time ago, and it seems to have been duplicated by Phenomenex (at least). Here's a link to a "picture" of the phase:

http://www.restek.com/catalog/view/11086

Short alkyl spacer to a "biphenyl group" two phenyls linked together.

Don't know whom exactly introduced the Diphenyl stationary phase, but at least Fortis and Agilent make and sell it. Here's a "picture" of the phase:

http://www.fortis-technologies.com/Fortis_Diphenyl.html

A bit longer of an alkyl spacer to two phenyl groups linked by a methine function.

I apologize, I really don't have any idea of differences in selectivity between these phases...but at least Fortis claims a greater selectivity for diphenyl over biphenyl for positional isomers. Maybe some folks have used both phases...I've used biphenyl for biocide separations from extracted wood samples in my past with good success.