D R Gere | PubMed Health

PubMed1992

Rapid robust separation of hydroxyproline and proline.

The presence of hydroxyproline, and the determination of the ratio of the secondary amino acids proline to hydroxyproline, in amino acid hydrolysates specifically identifies collagen and collagen peptides. o-Phthalaldehyde, and then 9-fluorenylmethyl chloroformate, were used to carry out sequential prederivatization of amino acid hydrolysates in an in-line high-performance liquid chromatography sample loop. After derivatization, reversed-phase high-performance liquid chromatography with a C-18 ODS Hypersil cartridge column was used to resolve the hydroxyproline and proline from all primary amino acids, with resolution and detection of hydroxyproline and proline within 2.0 and 2.8 min, respectively, at concentrations in the range of picomoles per microliter of derivatized amino acid. The assay has a turnaround time of 10.75 min.

Chromatography, High Pressure Liquid↗

PubMed1983

Supercritical fluid chromatography.

Chromatographic separations with a supercritical fluid as the mobile phase were suggested more than 20 years ago. Availability of commercial hardware makes this technique more widely usable today. Many separations by this method are now carried out with supercritical carbon dioxide as the mobile phase and packed liquid-chromatography columns as the stationary phase. Although carbon dioxide has many practical advantages, including its near-ambient critical temperature and minimal interference with spectrometric detection, the use of other supercritical fluids or addition of modifiers to carbon dioxide may extend the applications of this technique. Some mixtures that are difficult to analyze by other chromatographic methods may be susceptible to separation by supercritical fluid chromatography. Mixtures that have been separated with supercritical carbon dioxide include resin acids with the empirical formula C20H30O2 and ubiquinones from bacterial cell wall extracts of Legionella pneumophila.

Carbon Dioxide↗