Porous silicon-based potassium ion selective electrode

Porous silicon (PS)-based potassium ion selective microelectrode (K⁺ISME) was fabricated by using microelectronic planar process and electrochemical anodization etching technique. The apparent sensing area of the K⁺ISME is 8 mm by 8 mm. The calibration curve for the K⁺ISME is linear within a wide range of pK=1.0∼4.0. Its slope is 56 mV per decade, which is near Nernst response. The long-term stability of the K⁺ISME is good. The variation of the response is within ±2 mV during 2 months. Good performances of the K⁺ISME are attributed to large specific surface area and easily modified microstructure of PS.