In the adjacent image we show the raw signal (mV) from four individual ZP pH sensors.

In the test all four pH sensors are tested between pH 2 and pH 10 and the pH is cycled several times between these two values using increments of 1 pH unit at a time.

The sensitivity of each sensor is very similar, in that they show a very similar change in mV with each pH change. The difference between the pH sensors is the offset and so to increase accuracy it is useful to do a 1 point or 2 point calibration.