A method of determining hydrogen peroxide with a multiplex electrochemical sensor

A method of determining the presence and/or concentration of hydrogen peroxide in one or more aqueous solutions (122) using an electrochemical sensor (10) comprising:

• i. two or more front electrodes (11) comprising pores permeable to the aqueous solution (122) and comprising a sensitive surface (12) to the hydrogen peroxide;
• ii. one or more electrolytic conductor bridges (14) permeable to the aqueous solution (122);
• and
• iii. one back electrode (16) comprising at least a surface and optionally a support (13);
• wherein the front electrodes (11) are electrically connected via the one or more electrolytic conductor bridges (14) to the one back electrode (16);
• wherein the front electrodes (11) comprises pores above 0.2 μm of equivalent diameter that connect the external surface of the front electrode (11) and the one or more electrolytic conductor bridges (14);
• wherein the sensitive surface (12) of the front porous electrodes is a hydrogen peroxide platinum sensitive surface (12) including platinum derivatives such as black platinum and platinum nanomaterials;
• wherein the electrochemical sensor (10) is configured so that the one or more aqueous solutions (122) enters in contact with the back electrode (16) through the one or more electrolytic conductor bridges (14), which in turn enters in contact with the one or more aqueous solutions (122) through the pores of the front electrodes (11);
• wherein the electrochemical sensor (10) further comprises means (18) for determining the difference in the electrochemical state between the front electrodes (11) and the back electrode (16);
• and wherein the determination of such difference in the electrochemical state indicates the hydrogen peroxide presence and/or concentration in the aqueous solution (122).