Fig. 5.

Real-time application of the sensor. (a) Photograph of the sensor in the Teflon cell only (1) with a finger (2) and with a metal shield (3) during CO₂ gas monitoring of the finger. Transcutaneous sensing of CO₂ released from the first finger of the right hand corresponding to settings 1, 2 and 3 (shown in the coloured regions). (b) Response of the sensor to CO₂ gas released from the wrist when the sensor is placed directly on the skin. (c) Response when the sensor is kept in a Teflon cell with a circular opening in the middle (wrist band). The inset shows the arrangement of the sensor on the wrist.