Cell configuration with immobilised electrolyte solution

4 Cell configuration with immobilised electrolyte solution 

An important condition to be fulfilled in order to use the method for detection of sweat formation and its composition is that the electrodes are elec-trolytically in contact with each other. This is not a strict condition for urine detection and as an early-warning system for diabetes, because in these applications a qualitative detection is enough, and therefore one can start with dry electrodes. For diagnosis of cystic fibrosis, this is not possible because here a quantitative detection of salt concentration is expected. Therefore, one needs to start from a system with electrodes that are elec-trolytically in contact with each other right from the start of the experiment. For this purpose, water is immobilised in high-density cotton in which the conductive stainless-steel yarn electrodes are implemented. 

In order to evaluate the electrode configuration, similar experiments were performed as described in the previous section, and the results were compared in order to determine whether the electrodes behave identically in the absence and presence of cotton. As expected, similar results were obtained concerning the relationships Equation 10.1 is also valid for electrodes immersed in cotton that act as an immobilising substance for the electrolyte, but the value of k is different. Indeed, all experimentally obtained curves are shifted towards higher resistive behaviour, which can be explained by the fact that the presence of cotton forms a barrier for the conductivity of ions through the electrolyte solution. However, as explained in the previous section, k can be obtained by calibrating the electrode setup, so calibration in the presence of cotton circumvents the problem of different results in the absence and presence of cotton. 

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