Evaluation of miniaturised solid state reference electrodes on a silicon based component

A study of two different types of micro reference electrodes with respect to preparation and performance is described. The first, Type 1 Ag/AgCl, consists of a silver/silver chloride ink screen printed onto platinum on silicon. The second, Type 2 Ag/AgCl, uses the screen printed reference electrode just described, Type 1 Ag/AgCl, covered with a chloride doped vinyl ester resin. The latter eliminates some of the difficulties and drawbacks associated with Type 1 Ag/AgCl because the requirement for a constant chloride concentration in the analyte solution is removed when using Type 2 Ag/AgCl. Type 1 Ag/AgCl acted as a chloride selective electrode with a slope of 55.83 mV per decade for chloride activity and Type 2 hg/AgCl potential versus SCE varied from -40.1 to -20.3 mV for KCl concentrations of 10(-7) and 1 M, respectively. The performance of a commercially available macro solid state reference electrode (called MacroRefex in this work), fabricated from the same materials as Type 2 Ag/AgCl, was also investigated. (C) 1997 Elsevier Science S.A.