Exploring anthraquinone derivatives for effective peroxide detection in reheated palm oil: Insights and innovations

This study explores the reactivity of anthraquinone derivatives, specifically anthraquinone (AQ), 1,4-dihydroxyanthraquinone (1,4-DHAQ), and 1,2-dihydroxyanthraquinone (1,2-DHAQ), toward peroxide detection in reheated palm oil (RPO), with a focus on structure-reactivity relationships. Using a combination of UV-visible, fluorescence, and ¹H NMR spectroscopy, we demonstrated that only 1,2-DHAQ exhibited significant reactivity with tert-butyl hydroperoxide (t-BuOOH), attributed to its accessible hydroxyl group at the C2 position. In contrast, AQ and 1,4-DHAQ showed negligible activity due to non-reactive carbonyl centers and intramolecular hydrogen bonding, respectively. These experimental findings were supported by DFT-based binding energy calculations and molecular orbital analysis, confirming site-specific peroxide interaction with 1,2-DHAQ. To translate these findings into a practical sensing platform, we developed paper-based analytical devices (PADs) incorporating 1,2-DHAQ and evaluated their response in both model systems (1-decanol + t-BuOOH) and real RPO samples. The PADs showed concentration-dependent decreases in RGB intensity and fluorescence emission, consistent with peroxide-induced quenching behavior. Peroxide values (PV) were also measured using iodometric titration and correlated strongly with both optical responses (R² > 0.97), confirming peroxide specificity even in complex oil matrices. Overall, the study identifies 1,2-DHAQ as a structurally optimized, cost-effective sensing material for peroxide detection and highlights its practical application in oil quality monitoring using a simple PAD platform.