A Fe3O4-based chemical sensor for cathodic determination of hydrogen peroxide

A new cathodic scheme for hydrogen peroxide (H2O2) measurement by Fe3O4-based chemical sensor was described. The unique characteristic of electrocatalytic property was firstly investigated by voltammetry. And then the amperometric response of H2O2 was measured at - 0.2 V (vs. Ag/AgCl) by Fe3O4 modified glassy carbon rotating disk electrode. The kinetic parameter was also calculated from Koutecky-Levich plot, and the value was 6.4 x 10(-4) cm s(-1) in pH 3 citrate buffer. In order to benefit the possible biomedical applications, Fe3O4/chitosan modified electrode was also investigated in this experiment. There were several characteristic enhancements by the coated chitosan thin film for H2O2 sensor. The calibration curves were found to be linear up to 4.0 and 5.0 mM (r = 0.999) in pH 3 and 7 with the detection limits of 7.6 and 7.4 mu M L-1 (S/N = 3). The stability was evaluated by the results of half-life time (t(50%)) for 9 months at room temperature and 24 months at 4 degrees C.