抄録
A one-chip Ca2+ ion sensor integrated with a micro double junction Ag/AgCl reference electrode was microfablicated. The thin-film Ag/AgCl element used in the reference electrode features a polyimide protecting layer and the AgCl layer grown from a slit in the polyimide layer. The container for the internal KCl solution and a liquid-junction were formed with an SU-8 thick-film photoresist. KCl was incorporated in the micro container in a solid powdered form and the area was passivated with a silicone rubber. Another junction was formed at the end of the passivation. The double junction reference electrode could maintain a stable potential for approximately 80h. The Ca2+ ion-selective electrode was fabricated by forming an ion-selective membrane on one part of a silicon micro container formed by anisotropic etching. The one-chip Ca2+ ion sensor was constructed using the Ca2+ indicator electrode and the miniaturized liquid-junction reference electrode. A linear relationship was obtained between the indicator electrode potential and Ca2+ activity for Ca2+ activity higher than 10-4. Sensitivity was 30.3mV/decade.
