Chiral HPLC Columns

Astec PCAP

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P-CAP is a new bonding technology, primarily used in normal phase, for the separation of racemic compounds. This CSP technology is based on the reproducible polymerization of a cyclic diamine from surface of silica. This method offers maximum protection of the silica and excellent availability of the short chain polymer ligand that ensures high capacity. The resulting thin, ordered layer of polymer does not alter the porous structure of the silica. The repeating chiral moiety offers both structural conformation and hydrogen bonding interactions as the driving mechanisms. Preparative separations can be run in a variety of solvents (without any large impact on selectivity) to meet solubility requirements. As a result of the juxtaposition of the binding sites, molecules with two or more functional groups demonstrate the best selectivity. Separations have been run in pure acetone, heptane/ethanol, dichloromethane/methanol and ethylacetate.

P-CAP-DP™ expands the capabilities and is complementary to the original P-CAP chiral stationary phase, the latter used primarily in normal phase for separation of racemic compounds. The introduction of the π system, in combination with the chiral hydrogen bonding capabilities offers new opportunities for chiral selectivity. The additional bulk from the aromatic rings further enhances steric effects. P-CAP-DP™ is generally used with two basic mobile phase systems: (1) normal phase heptane/IPA or ethanol; or (2) the polar organic mode employing acetonitrile/methanol. Volatile acids and buffers can be used to enhance peak efficiency when needed or to enhance ion detection for MS platforms. Additional racemates resolved with high selectivity include hydroxycarboxylic acids, alcohols, sulfoxides, esters, amides and lactones and N-blocked amino acids. There are no known limitations on the kind of solvents that can be used with these phases including halogenated compounds. The well ordered polymer layer is unaffected by solvent changes and allows for excellent efficiency and reproducibility.

Both P-CAP and P-CAP-DP™ are covalently bonded polymer based chiral stationary phases with high stability, no memory effect, high sample loadability, and easy scale-up. Selectivity can be obtained in a variety of solvent choices with different efficiencies. Salt and/or acetic acid can be added to improve efficiency or enhance detection in mass spectrometry. P-CAP-DP uses similar protocols as P-CAP and can be optimized for either normal or polar organic mobile phase. It is less polar than P-CAP, and ideal for sub- and supercritical fluid applications. The elution order of compounds can be reversed in the (R,R) versus (S,S) configuration. P-CAP is manufactured under license from La Sapienza, Università degli Studi di Roma.