Blood Oxygen Sensor Using a Boron-Doped Diamond Electrode

The electrochemical behavior of oxygen (O-2) in blood was studied using boron-doped diamond (BDD) electrodes. Cyclic voltammogram of O-2 in a 0.1 M phosphate buffer solution solution containing 1 x 10(-6) M of bovine hemoglobin exhibits a reduction peak at -1.4 V (vs Ag/AgCl). Moreover, the scan rate dependence was investigated to study the reduction reaction mechanism, which was attributable to the reduction of O-2 to H2O2 via two electrons. A linear calibration curve was observed in the concentration range of 86.88-314.63 mg L-1 (R-2 = 0.99) with a detection limit of 1.0 mg L-1 (S/B = 3). The analytical performance was better than those with glassy carbon or platinum electrodes as the working electrode. In addition, an application to bovine blood was performed. The O-2 concentration in the blood measured on the BDD electrodes was compared to that measured using an OxyLite Pro fiber-optic oxygen sensor device. Both methods gave similar values of the O-2 concentration in the range of similar to 40 to 150 mmHg. This result confirms that BDD electrodes could potentially be used to detect the O-2 concentration in blood.