The sol-gel method was used to prepare binary metal oxide (IrO2-RuO2) pH sensor. The electrodes that mole percent compositions (mol%) of IrO2 and RuO2 were 70:30 and 30:70 were selected. The characterizations of Nernstian response over pH range, response rate, interference on alkaline metals and reproducibility were investigated. Also the electroanalytical properties of these electrodes were evaluated in comparison with a commercial glass pH electrode. The composition of IrO2:RuO2 70:30 mol% was chosen as better electrode formulation. The electrode was not susceptible to the action of interfering ions such as Li+, Na+ and K+.

Lead (II) ion selective poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore as a sulfur containing sensing material is successfully developed. The electrode exhibits good linear response of 25.6 mV / decade (at 20±0.2℃, r2=0.995) within the concentration range of 1.0×10-1~4.0×10-7 M Pb (II). The composition of this electrode was Ionophore : PVC : dioctylphthalate : potassiumtetrakis(4-chlorophenyl)borate : Oleic acid = 5.0 : 20.0 : 25.0 : 4.0 : 5.0. When we consider the results of using different composition electrodes based on only one potassiumtetrakis(4-chlorophenyl)borate or Oleic acid liphophlic additive, poly(aniline) solid contact electrode based on Tetramethylthiuram monosulfide ionophore with potassiumtetrakis(4-chlorophenyl)borate and Oleic acid liphophlic additive had the best result in response characteristics. The electrode shows good selectivity for lead (II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. This electrode is suitable for use with aqueous solutions of pH 3.0 ~ 7.0 and their standard deviation in the measured emf differences was ±2.94 mV at Tris buffered lead sample solution of 1.0×10-2 M and ±2.82 mV at Tris buffered lead sample solution of 1.0×10-3 M. Their stabilization time was less than 710 s. and response time was less than 16 s.