Patent ID: 8142641

Claim:
An electrochemical sensor comprising a mounting having a screen printed array of electrodes located thereon, the array comprising a reference electrode, a counter electrode, and a plurality of working electrodes, wherein the working electrodes include a first working, electrode and a second working electrode that are each overlaid with an insulating layer of insulating material, the insulating layer of each of the first and second electrodes having an array of apertures exposing a respective array of working regions of the working electrodes, wherein the first working electrode includes a first reagent layer that overlies the apertures within the insulating layer, the first reagent layer being impregnated with potassium iodide and a phthalate buffer, and the second working electrode includes a second reagent layer that overlies the apertures within the insulating layer, the second reagent layer being impregnated with TMB and a buffer.