Facile Preparation of Fe(3)O(4)/C Nanocomposite and Its Application for Cost-Effective and Sensitive Detection of Tryptophan

In this study, we reported facile synthesis of Fe(3)O(4)/C composite and its application for the cost-effective and sensitive determination of tryptophan (Trp) in human serum samples. Fe(3)O(4)/C composites were prepared by a simple one-pot hydrothermal method followed by a mild calcination procedure, using FeCl(3)∙6H(2)O as Fe(3)O(4) precursor, and glucose as reducing agent and carbon source simultaneously. The Fe(3)O(4)/C composite modified glassy carbon electrode (Fe(3)O(4)/C/GCE) was prepared by drop-casting method. The microstructure and morphology of Fe(3)O(4)/C composite was characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Due to large specific surface area and synergistic effect from Fe(3)O(4) nanoparticles and carbon coating, Fe(3)O(4)/C composite showed excellent electrocatalytic activity toward the oxidation of Trp. As a result, the proposed Fe(3)O(4)/C/GCE displayed superior analytical performances toward Trp determination, with two wide detection ranges (1.0–80 μM and 80–800 μM) and a low detection limit (0.26 μM, S/N = 3). Moreover, successful detection of Trp in human serum samples further validate the practicability of the proposed sensor.