By Michael Breslav on Tuesday, May 11, 1999 - 06:08 am:
Greetings,
I need to isolate a compound that is very unstable in the presence of water. However conventional normal phase separation with a variety of organic phase containing mixtures on a silica or on a cyano phase does not provide good resolution or caused breakdown of the product (like THF/silica). I also tried alumina oxide with a little success. Is there an alternative to silica/cyano? Size exclusion chromatography will not provide satisfactory loading. I am not sure about HILIC without water or if I can use phenyl phase or even Chiroltech enantioselective columns just because they can be used with organic solvents? I am not aware of any new organic polymeric stationary phases that could work with organic solvents.
Any advice is appreciated.
Michael Breslav
R.W.J. PRI
Spring House, PA
mbreslav@prius.jnj.com
By Karen on Wednesday, May 12, 1999 - 06:15 am:
I would suggest trying HILIC because the active silica or alumina groups would no longer be exposed. HILIC can be run with alcohols instead of water (Anal. Chem. 69, 3038-3043). Probably other polar solvents would also work.
By B.Buglio on Sunday, May 16, 1999 - 06:19 pm:
Teicoplanin and vancomycin cyclodextrin columns have nonchiral applications and can be used in the normal or revervsed phase modes.
By Tony Herlt on Monday, May 17, 1999 - 11:43 pm:
Perhaps it is worth trying the DIOL (2,3-dihydroxypropyl) stationary phase. Merck for example make this phase in their Lichrospher range and we have sometimes found this superior to silica and cyano.
Tony
By Anonymous on Saturday, June 19, 1999 - 02:14 am:
Dear Michael,
Hypersil offer a column called Hypercarb.
It can be used as a normal phase or reverse phase column under pH conditions from 0 to 14.
It has an enhanced selectivity for closely related compounds such as geometric isomers and diasterioisomers. It is excellent for the separation of highly polar compounds and can perform separations based on compound shape.
The material is well known for it's extensive life-time.
I've used this product a lot in the past couple of months for all kinds of unusual separation that cannot be performed on silica. I think it would be well worth giving it a go.
You can get more info on this product from ThermoQuest in Needham, MA. Their telephone no. is 1-800-292-6088.
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