Comprehensive and quantitative stability study of ascorbic acid using capillary zone electrophoresis with ultraviolet detection and high resolution tandem mass spectrometry

: Ascorbic acid is a powerful antioxidant compound involved in many biological functions, and a chronic deficiency is at the origin of scurvy disease. A simple, rapid and cost effective CE method was developed for the separation and simultaneous quantification of ascorbic acid and the major degradation products: dehydroascorbic acid, furfural and furoic acid. Systematic optimisation of the conditions was performed which enabled baseline separation of the compounds in less than 10 min. Quantification achieved was validated successfully in terms of linearity, precision, accuracy, LOD and LOQ. Stability studies were conducted using degradation samples to evaluate the stability indicating aspect of the CE method. In addition to simultaneous quantification of ascorbic acid alongside to the degradation products, stability studies demonstrated the possibility using CE to separate and identify the major degradation products. Thus, high resolution tandem MS experiments were conducted in order to identify an unknown degradation product separated by CE and significantly present in degraded samples. Comparison of MS data and CE electropherograms allowed to identify unambiguously trihydroxy-keto-valeraldehyde. Finally, CE was successfully applied to evaluate the composition of different pharmaceutical preparation of ascorbic acid. Results showed the excellent adequacy of the CE method due to the separation of excipients from the compounds of interest which demonstrated the relevance of using an electrophoretic separation in order to perform comprehensive stability studies of ascorbic acid. This article is protected by copyright. All rights reserved.