Electrochemical dopamine sensor based on superionic conducting potassium ferrite.

Ionic liquid composite electrodes have been widely utilized for the fabrication of electrochemical biosensors. However, the biosensing electrode modified with ionic conducting solids remains unexplored. Herein, we prepared a superionic conducting potassium ferrite (K2Fe4O7) under hydrothermal conditions for modifying glassy carbon electrode (GCE). The modified electrode (K2Fe4O7/GCE) showed an excellent electrocatalytic activity towards the oxidation of dopamine (DA). The oxidation peak currents increased linearly with increasing DA concentrations in the range of 1 μM-140 μM, and the detection limit is 0.22 μM (S/N = 3). The developed DA sensor exhibited not only good selectivity for the determination of DA without interfering from ascorbic acid (AA), uric acid (UA), glucose and inorganic ions, but also good reproducibility and stability. Furthermore, the sensor was applied to determine DA concentration in bovine serum and obtained a satisfied result. This study provides a new approach for developing electrochemical biosensors based on ionic conducting solid materials.