Nanodiamond-like bixbyite FeMnO3 anchored on N-doped graphene for enhanced electrocatalytic detection of the vitamin E analogue Trolox in fruit samples

Abstract

Accurate quantification of antioxidant compounds is essential for evaluating food quality, antioxidant capacity, and product authenticity. Trolox (TRX), a water-soluble vitamin E analog, is widely used as a reference antioxidant in food analysis. Here, an iron manganese oxide on nitrogen-doped graphene (FeMnO 3 /NGR) nanohybrid was developed as an electrochemical sensor for TRX determination in blueberries. Diamond-like bixbyite FeMnO 3 and NGR nanosheets were synthesized hydrothermally, followed by ultrasonic treatment, and assembled into a conductive heterostructure. The nanohybrid combines the high conductivity of NGR with the redox-active Fe/Mn catalytic sites of FeMnO 3 , enhancing charge transfer and electrocatalytic oxidation of TRX. The sensor exhibited a wide linear range (0.019–910 μM) with low detection and quantification limits of 0.012 and 0.040 μM, respectively. It also demonstrated excellent selectivity, stability, and reproducibility, enabling the accurate quantification of TRX in blueberry extracts. This FeMnO 3 /NGR platform offers a sensitive and reliable approach for antioxidant analysis and food quality assessment in complex food matrices.