Hydrogen-selective microelectrodes based on silicon needles

The fabrication of hydrogen-selective microelectrodes on silicon needle-shaped substrates is described. The microelectrodes are based on an ion-selective poly(vinyl chloride) (PVC) membrane with an intrinsically conducting polymer (polypyrrole (PPy)) solid contact layer. The polypyrrole is prepared with the dopant anion cobaltbis(dicarbollide) [3,3'-Co(1,2-C2B9H11)(2)](-), which gives a high stability to the polymer layer. The performance of the resulting solid-contact ion-selective microelectrodes (SCISME) is investigated by using potentiometric measurement and electrochemical impedance spectrometry. The feasibility of the fabrication technology is demonstrated and the devices operate satisfactorily, with a response showing good sensitivity and selectivity against common interfering cations in background solutions. The SCISME has been developed for organ monitoring during cardiac surgery or during transportation for transplants. (C) 2003 Elsevier Science B.V. All rights reserved.