Abstract: Unfolded hemoglobin was immobilized onto the surface of a clay-gold nanoparticles (Clay-AuNPs) modified glassy carbon electrode (GCE) by the physical adsorption method, and then diamine oxidase (DAO) was immobilized with 2.5% glutaraldehyde as a crosslinking agent. The resulting electrochemical biosensor had good detection performance for cadaverine. The electrode modification system, DAO concentration, the type of mimic peroxidase, the stability of the modified electrode and the test conditions were optimized. The modified electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Furthermore, the method was used to detect the cadaverine content in mackerel. The results showed that under the optimized conditions, the response current of the sensor had a good linear relationship with cadaverine concentration in the range between 2.0 × 10-12 and 1.0 × 10-11 mol/L (r = 0.991), and the detection limit (RSN = 3) was 6.7 × 10-13 mol/L. The spiked recoveries of cadaverine in mackerel samples by this biosensor method ranged from 82.2% to 109.1%. Thanks to its good reproducibility and stability and high sensitivity, this method is suitable for the determination of cadaverine in fish samples such as mackerel.

Key words: cadaverine; biosensors; diamine oxidase; gold nanoparticles; mackerel