hi,
i am looking for resources and opinions on the techniques to separate chiral amino acids and derivatives by HPLC.
what i need is a method development good for both analytical and preparative aspects.
so far my knowledge is:
crown ether based column is good for primary amines, but i am not sure about the derivatized amino acids (which means no free N-H available, for example)and in terms of preparative part such as availability and loadability.
it is said that the best choice would be ion-exchange/ligand exchange LC, but i could hardly find a few columns and most of them contain metal additives such as Chirex 3126 needs copper salt in mp,that is not good from preparative aspect. and i could not find any resources talking about chiral method development.
Daicel columns also need additives for simple amino acids and not good for non-chromophore amino acids.
ASTEC has a lot of examples by chirobiotic columns, but again i don't know about the loadability, since the CSP is pretty large biomolecules and my impression that ASTEC column has short lifetime, especially on prep size.

will appreciate any help.

EKA Kromasil?

http://www.kromasil.com/products/products/chiral/index.html

thanks,
but i don't see many amino acids application there.

Although there are many suppliers of chiral columns, the company which is by far the leader in this area is Daicel: http://www.chiraltech.com You might want check out their catalog.

thanks.
i use Daicel all the time, their columns are my main weapon on chiral separation. but for amino acid, it is no good. needs a lot of additives and can't do it with no chromophore native AA.

When I read the original message, I thought Tom Beesley at Astec might have a good technical response, so I forwarded the message to him. He responded with the following message to a yahoo email address, but I thought his response should also be posted here for general access. So here it is. I hope no one feels it is too commercial.

Dear Chromatographer,

The separation of alpha, beta and gamma amino acids as well as cyclic, unusual, and any end blocked amino acid is Astec's speciality. The Chirobiotic T and TAG are the work horses in this area, usually separating in simple alcohol/water mixtures. Those amino acids with multiple functional groups like his, arg, asp, or glu require the addition of a volatiIe buffer like ammonium acetate. In the Chirobiotic Handbook, which can be found on our web site at astecusa.com, you will see an extensive list of free and N-blocked amino acid separations. We can also send you chromatograms from DSM and Chirotech that use these columns routinely for these applications. We also have a recent application report presented at the ISCD meeting in Japan demonstrating minimum levels of detection techniques for amino acid analysis. With your address we can forward this information to you.

On the issue of capacity, the prep applications in this area run from 3-7 mgs racemate/gram CSP (chiral stationary phase), which is well above the average. This means loadings of 100 to 300 mgs on a 1" X 25 cm column. Much work has gone on in this area for heavy isotope labeled amino acids. The acetylated amino acids show very large increases in solubility and selectivity, and acetylation is highly recommended for those amino acids with low solubility in alcohol/water mobile phases.

Stability: the macrocyclic glycopeptides used for the Chirobiotic phases are linked with five covalent bonds. They are stable to all chromatographic solvents, including chlorinated solvents. Literature reports clinical applications of 2500 to 4000 plasma samples being processed on a single column with no observable change. These columns have been widely used in large scale prep and at linear velocities beyond the capability of most CSP's. We guarantee the stability as long as they are used within the pH range of 3.5 to 6.9.

We would be happy to answer any further questions regarding your needs, and if you will send us your address we will send to you the additional information cited above as well as the Chirobiotic Handbook.

Best regards,

Tom Beesley
Advanced Separation Technologies Inc