Novel sensors for potassium, calcium and magnesium ions based on a silicon transducer as a light-addressable potentiometric sensor Original Research Article

Potentiometric cation sensors using a silicon transducer, light-addressable potentiometric sensor (LAPS) and ion-recognition elements are described, and their performance are discussed. In the silicon transducer, an Al2O3 layer was used as an insulating layer. On the surface of the Al2O3 layer, ion-recognition element such as valinomycin, 18-crown-6 ether, bis[di(n-octylphenyl)phosphato]calcium(II) and ETH1117 were immobilized in the matrix of poly(vinyl chloride) film. Potassium tetrakis (p-chlorophenyl)borate was used as a lipophilic salt. The K+, Ca2+ and Mg2+ sensitive-silicon electrodes showed responses similar to those of the corresponding ion-selective electrode. Furthermore, calcium sensing properties of lipophilic anion concentration were studied. It was shown that the presence of lipophilic anion increased the slope.