Fluorimetric determination of free hydroxyproline and proline in blood plasma

A selective and sensitive assay of hydroxyproline in blood plasma is presented. The technique uses ion exchange chromatography followed by reaction with 7-chloro-4-nitrobenzofurazan (NBD choloride) and continuous recording of the resulting fluorescence (gamma ex=465 nm, gamma fl=535 nm). Proline and prolyl-and hydroxyprolyl-peptides can also be measured by this system. For hydroxy proline, the method is more sensitive than procedures using ninhydrin or p-dimethylaminobenzaldehyde.