Dansyl Amino-Acids Behavior on a Radial Pak C18 Column. Derivatization of Grape Wine Musts, Wines, and Wine Vinegars

Production, isolation and identification of low molecular mass peptides from blue cheese by high performance liquid chromatography

The blue cheese nitrogenous fractions soluble in water and in 5% phosphotungstic acid (PTA) were analysed by HPLC after 3–180 d ripening. In the water-soluble fraction, in addition to four or five major peaks corresponding to amino acids, there were many minor peaks, which increased during ripening. The low molecular mass peptides, soluble in 5% PTA, showed ripening-induced increments. A method combining precipitation with 5% PTA, gel permeation and subsequent HPLC was used to isolate some peptides of cheese. Four peptides containing between seven and ten residues were isolated and their amino acid composition and N-terminal residues determined.

Determination of 27 dansyl amino acid derivatives in biological fluids by reversed-phase high-performance liquid chromatography

The concentrations of free amino acids in plasma and in ascitic liquid of mice with Ehrlich ascitic tumours were determined by reversed-phase high-performance liquid chromatography using pre-column derivatization with Dns chloride and UV detection at 254 nm. Sample preparation is simple, and the Dns derivatives are stable. Complete separation of 27 amino acids, including proline and cysteine, was achieved in 70 min with detection limits of less than 25 pmol. There was no interference from Dns-Cl, Dns-OH and Dns-NH2. Retention time reproducibility was better than 1%. The described method enables a rapid, economical and reproducible quantification of free amino acids in biological fluids.