Advances in Analytical Methods for Flavonoid and Polyphenol Quantification: From Conventional Assays to Modern Sensor Technologies

Abstract

Flavonoids and phenols are diverse classes of plant-derived secondary metabolites well-recognised for antioxidant, anti-inflammatory, cardioprotective, and anti-cancer properties. It is essential to accurately measure them for application in food science, medicine, and research to understand pharmacokinetics, and validate their therapeutic potential. Simple tests such as Folin-Ciocalteu, aluminium chloride, and pH - differential methods are low cost and easy to perform but have limited specificity, as other matrix compounds may interfere. Advanced analytical techniques such as high-performance liquid chromatography (HPLC), ultra-high-performance liquid chromatography (UHPLC), liquid chromatography–tandem mass spectrometry (LC-MS/MS), high-resolution mass spectrometry (HRMS), and capillary electrophoresis (CE) offer superior precision and enable the identification of specific flavonoid and polyphenol compounds. In recent years, modern innovations- including nanotechnology-based sensors, artificial intelligence and molecularly imprinted polymers have further enhanced detection accuracy, allowing for the quantification of these compounds at trace levels in complex matrices such as food products, plant extracts, biological fluids, and environmental samples. Despite these improvements, challenges such as structural diversity, low analyte concentration, compound instability, and co-extractive interference remain. Strategies such as optimized extraction protocols, solid-phase extraction (SPE), microextraction techniques, chemometric data analysis, and hyphenated analytical systems help overcome these limitations. Future perspectives emphasize artificial intelligence–assisted data processing, portable sensor technologies, green analytical chemistry approaches, and lab-on-a-chip systems.  These emerging approaches are expected to enable rapid, sensitive, and sustainable detection platforms for future clinical, food, and pharmaceutical applications.