Abstract: In this study, a novel electrochemical sensing strategy with high sensitivity and selectivity was developed for the quantitative detection of L-tyrosine (L-Tyr). The iron-doped mesoporous carbon nanosphere (Fe-MCN) composite was successfully prepared via the coordination-assisted polymerization assembly method. The morphology and structure of the material were systematically characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The Fe-MCN composite was modified on the surface of a glassy carbon electrode (GCE), yielding a Fe-MCN/GCE electrochemical sensor. The electrochemical behavior and kinetic process of L-Tyr on the surface of Fe-MCN/GCE were investigated. Under the optimal conditions (pH 5.5), the oxidation peak current (Ip) showed a good linear relationship with L-Tyr concentration (c) within the range of 0.05–25 μmol/L: Ip = 0.04c + 0.013 (R2 = 0.997 4), and the detection limit (LOD) was 0.022 μmol/L. This sensor exhibited excellent repeatability, reproducibility, and interference resistance. It was successfully applied in the detection of L-Tyr in actual samples, including nutritional supplements and milk, with spiked recoveries ranging from 100.15% to 104.00%. This study provides a high‑performance sensing platform for the rapid and sensitive detection of amino acids in foods.

Key words: iron doping; mesoporous carbon nanospheres; electrochemical sensor; L-tyrosine