Conductivity measurements with miniaturised thin film metal electrodes

Impedance and admittance measurements in electrochemical cells were carried out using Au and Pt thin film metal electrodes to show the abilities of miniaturised thin film conductivity sensors. The frequency dependence of the ion concentration sensitive range of interdigital structures (IDS) with different miniaturisation scales is shown. Low scale miniaturised IDS should be applied at low frequencies (about 500 Hz) using the common two electrode technique, large scale miniaturised at different and higher frequencies using the four electrode technique. For both cases calibration curves are given for the example of 10-4 to 1 mol/1 KCl solutions.