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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Fabrication of a needle-type pH sensor by selective electrodeposition
Author(s): Woo-Hyuck Choi; Ian Papautsky

Paper Abstract

This manuscript reports on the development of a needle-type sensor for in situ on-site measurement of pH. Conventional pH microelectrode sensors are fabricated by pulling glass pipettes and applying ion-selective films at the tip. However, these sensors suffer from low fabrication yields and short sensor lifetime due to disruption or loss of the ion-selective membrane after repeated use. The developed needle-type sensor is fabricated by meniscus etching and takes advantage of the MEMS batch fabrication techniques. The sensor is based on the ion-selective properties of iridium oxide film, which was deposited at the sensor tip by electrodeposition. The sensor exhibited a Nernstian response with sensitivity of ∼62 mV/pH in the pH 2 to 12 range. The sensor also exhibited a fast 5 s response and a lifetime of ∼2 months when stored in a pH7 buffer solution, which is substantially longer than that of the conventional pulled-pipette sensors.

Paper Details

Date Published: 1 April 2011
PDF: 4 pages
J. Micro/Nanolith. MEMS MOEMS 10(2) 020501 doi: 10.1117/1.3580751
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 10, Issue 2
Show Author Affiliations
Woo-Hyuck Choi, Univ. of Cincinnati (United States)
Ian Papautsky, Univ. of Cincinnati (United States)

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