Opinion on chiral column shopping list

[Trishia]

Well, I was put in charge of buying a set of chiral columns for our high-throughput catalysis facility here at the University. I first had to educate myself since I did not know much about chiral stationary phases. Here is what I am thinking of settling on (we will study a wide variety of molecules including heterocycles, small organic molecules, small-to-medium aliphatic methathesis products, lactones, imines, etc. etc.)

Chiral Tech's IA, IB, AS-H, OJ-H, OB-H, OF, OG, OK (+ some doubles)
Astec's Cyclobond I 2000 SN and Chirobiotic V and possibly R; B-DM, B-PM, B-PH, G-TA, B-DA, B-TA (but those are for the GC).

Any opinions/suggestions...?


Thanks,

Trishia

[tom jupille]

I would add one of the bound-protein columns to your shopping list. They allow more modification of selectivity via mobile-phase changes than the other types (that's the good news). The bad news is that they are expensive, fragile, and easy to overload.

[Bruce Hamilton]

The most important aspect of chiral columns is their lack of robustness, it's much easier to kill them with cruddy samples or incorrect solvents. You really need to look at guard columns for them as well.

I would strongly recommend that you talk to the column manufacturers about your needs and the best solution for your situation. You are proosing to have a wide variety of mobile phases, some of which will kill cellulose columns quickly, so the configuration of your system will be important.

As you presumably know, the major categories are:-
1. Cellulose triesters or carbamates ( eg Chiralcel )
2. Inclusion types ( eg cyclodextrins, crown ethers, polyacrylates etc. )
3. Brush type ( Pirkle ) - pi-donor, pi-acceptors, ( eg DNB-Leucine, Whelk )
4. Proteins ( albumin, glycoprotein, eg Vancomycin )

I would also go with less of the cellulose types and add some brush type, eg Whelk from Regis Technologies, and/or Chirex from Phenomenex.

I suppose it's my ignorance about HT synthesis, but I'd question whether you need to purchase so many columns at once. One or two columns of each of the major chiral column types would seem more cost effective, and then build your requirements from there.

However the most critical part of any purchase is to clearly define your requirements and then talk to the technical people at several relevant manufacturers. Apart from Diacel, I've found them to be very helpful and they respond quickly to enquires.

Bruce Hamilton

[Bruce Hamilton]

I would add one of the bound-protein columns to your shopping list. They allow more modification of selectivity via mobile-phase changes than the other types (that's the good news). The bad news is that they are expensive, fragile, and easy to overload.

Hiding in the alphabet soup was Chirobiotic V, which is a vancomycin column that is fairly general purpose.

Bruce Hamilton

[Trishia]

Hi there,

Oh yes, I'm definitely getting a whole bunch of guard columns for these.

I have looked into Regis' Pirkle phase columns (as well as into their protein Chiral AGP). I know that Pirkle phase require the analytes to have an aromatic pi-donor or pi-acceptor group (such as dinitrobenzoyl) - some with more precise requirements; that cyclodextrins require them to bear an aromatic function (except terpene alcohols and steroids); and that Protein phases require analytes with a ring close to the chiral center and at least one H-bond site close by). I believe Cellulose columns do not have any speficic requirements (correct me if I'm wrong) and I am unsure about Macrocyclic antibiotic phases... (if anyone can fill me in, that'd be great)... It was sort of my reasoning behind concentrating more on cellulose columns and getting a few of the other phases.

I suppose it's my ignorance about HT synthesis, but I'd question whether you need to purchase so many columns at once. One or two columns of each of the major chiral column types would seem more cost effective, and then build your requirements from there.
I completely agree with you. Unfortunately, we are buying this equipment on a grant and if we don't spend the money allocated, we lose it (which would be way too sad)...


However the most critical part of any purchase is to clearly define your requirements and then talk to the technical people at several relevant manufacturers. Apart from Diacel, I've found them to be very helpful and they respond quickly to enquires.

I have been in correspondance with Daicel, Astec and Agilent and have found them (and their web resources) to be of a great help.

Thanks,

Trishia.

[zoom]

You might want to consider some of Daicel's reversed-phase chiral columns as well -- especially if you will be dealing with acidic compounds.

Also, the Ceramospher RU-2 column seems to be a good, general-purpose chiral column.