Polar organic mode Chiral chromatography

[Mike H.]

I've been scouring the internet looking for information on this mode without success. Can anyone tell me what parameters if any affect retention time in this mode? Thank you. Alternatively any links with the theory behind this separation mode would be much appreciated.

[Andy Alpert]

Do you mean a chiral column that's eluted with a mobile phase that's predominantly organic? It switches over to functioning in the HILIC mode. There are several papers in the literature on the subject (in which the authors didn't always appreciate what was going on). If this is what you have in mind, let me know and I'll dig up some references.

[Mike H.]

I'm not sure. Let me detail the conditions. Chirobiotic T column, MP is 0.1% Ammonium formate in MeOH. If this was what you were talking about, I'd appreciate any information on the subject.

A brief background for what I'm trying to do. I'm using normal phase conditions to resolve a racemic compound. Conditions are as follows, 90:10:0.4 Hexane:EtOH:TEA, 40°, Chiracel AD-H column. The parameters are a little harsh because the compound is basic and tails a bit. This method is adequate for a racemic mixture, but isn't sensitive enough to detect an LOQ of 1%. I haven't been able to modify the conditions, sample concentration, sample load such that I can see at 1% level. So I was going to try a different technique ie. polar organic mode. Unfortunately I'm not familiar with it and I'm struggling to learn on the fly. Any suggestions will be appreciated.