At Zimmer and Peacock we are the only manufacturer of screen printed electrodes, biosensor, sensors and medical diagnostics who wafer-map our electrodes.
For certain types of electrochemical sensors the signal is proportional to the working electrode area and so ZP is unique in that we functionally test the working electrode as part of our manufacturing process.
In the adjacent image we have tested 52 electrodes with a standard solution using cyclic voltammetry. We have measured the peak height and have collected all the data we can see how the signal/peak height changes across the wafer. We can see that for this wafer our coefficient of variation is approximately 10%.
If someone was using this wafer to make sensors where the method of analysis was EIS (electrochemical impedance spectroscopy) or an amperometric technique we would report advise that the best variation they could expect is 10%, if they wanted better precision we would select electrodes from the wafer which we would take forward to convert into sensors.