High-Precision Online Total Phenolic Compounds Analysis Oxidized by Folin-Ciocalteu: Application to Ziziphus Jujuba Extract

This study introduced a new methodology for analyzing total phenolic compounds using an on-line oxidation technique with a continuous flowing carrier stream system. The method utilized visible spectrophotometric measurement at 765 nm to detect oxidized phenols by Folin Ciocalteu, resulting in blue chromophores. The automated process allowed for rapid sampling (11 samples per hour), simplicity, low reagent consumption, and high specificity. It demonstrated good linearity (10-50 mg/mL), excellent precision (RSD < 0.4%), and a detection limit of less than 0.03 g/mL. The method was successfully applied to measure total phenolic compounds in Ziziphus Jujuba fruit extract, suggesting its potential as a quality-control tool for routine quantitative analysis in various matrices, with applications in health, environmental sciences, and physiological and metabolic research.