Sensor for hydrogen peroxide based on Prussian Blue modified electrode: Improvement of the operational stability

Improvement of the operational stability of amperometric sensors based on Prussian Blue (PB) modified glassy carbon electrodes is presented. The long term performance of the sensors was evaluated by injection of hydrogen peroxide (5 mu M in potassium buffer) solutions in a flow-injection system during a period of 5 - 10 h. The following parameters were investigated and correlated with the performance of the sensor: the times for electrodeposition and electrochemical activation, temperature, storage time, pH, composition of the buffer solution and of volume sample injected. These analytical characteristics of the modified electrode can be emphasized: initial sensitivity of 0.3 A cm(-2) M-1, detection limit of cn. 0.5 mu M, precise results (r.s.d.< 1.5%) and possibility to carry out around 50 samples (50 mu L) per hour.