The normalised change in output voltage of the WOLF sensors
to IBS and CRC samples (with all responses averaged) is shown in
Fig. 2. This highlights both the overall similarities in response to all
urine samples and the more subtle variations used to find distinction between these two disease groups. There is generally a
positive change in current produced from these sensors, which is
expected considering an increase in analytes can only cause a
larger ionic current within the cells. These responses are at least
partially produced by an increase in humidity from the headspace
of the sample (which approximately changes from 6.8% to around
14%). However, individual sensor responses vary between different
samples independently of humidity levels, proving the presence of
gases and volatile groups being detected.