SIMULTANEOUS DETERMINATION OF CREATININE, URIC, L(+)-ASCORBIC AND OROTIC ACIDS IN MILK BY REVERSED-PHASE ION-INTERACTION HPLC CHROMATOGRAPHY

Separation methods have been developed by means of reversed-phase ion-interaction HPLC chromatography, using octylamine ortho-phosphate as the interaction reagent. In particular the separation of some antioxidants of relevant interest (known also as radical scavengers) such as L(+)-ascorbic acid, uric acid, orotic acid and cysteine, as well as the separation of creatine and creatinine have been performed. The results have been applied to the analysis of different kinds of milk, namely a diary farm milk, a commercial whole fresh milk and a UHT-sterilized one: creatinine, uric, L(+)-ascorbic and orotic acids were identified and quantified.