Post-column derivatization system for the fluorimetric determination of guanidino compounds with ninhydrin by reversed-phase ion-pair high-performance liquid chromatography.

A post-column derivatization system for the fluorimetric determination of guanidino compounds by high-performance liquid chromatography was developed. A mobile phase containing ninhydrin was used as the fluorigenic reagent. Ten guanidino compounds were separated within 25 min on a Nucleosil C8 (5 microns) column (15 cm X 4.6 mm I.D.) by isocratic, reversed-phase ion-pair chromatography and detected as fluorophors derived from condensation with ninhydrin in an alkaline stream. In this simplified system only two pumps required to deliver the mobile phase and the alkaline solution. This method was applied to serum from patients on haemodialysis therapy.