Enzyme-free electrochemical sensor based on Fe

An organic and inorganic nanocomposite was prepared as an electrochemical ferulic acid (FA) sensor. A highly water-soluble sulfonated PEDOT (PEDOT-S) film was drop cast onto a screen-printed carbon electrode (SPCE), followed by the deposition of Fe2O3 hollow spheres (HS). The sulfonate groups in the PEDOT-S underlayer enhance hydrophilicity and promote strong interactions with polar Fe2O3 HS, resulting in a uniform surface with a high electroactive area. The fabricated electrodes and materials were characterized by XRD, FTIR, FESEM, TEM, and XPS techniques. The modified electrode Fe2O3/PEDOT-S/SPCE was employed successfully for the enzyme-free electrochemical sensing, and notably, the sensor demonstrated excellent selectivity towards FA detection. The sensor exhibited two distinct linear detection ranges for FA, specifically 0.2 µM – 8 µM and 8 µM – 190 µM. Additionally, the limit of detection (LOD) was determined to be 0.05 µM (S/N = 3.3). Importantly, the Fe2O3/PEDOT-S/SPCE was applied to FA detection in commercially available food samples (apple, tomato, buckwheat) and beverage samples (wine, grape juice, orange juice), achieving recoveries ranging from 93.5% to 98.3%. These results indicate the practical applicability of the FA sensor in real sample analysis.