Reference-Electrode Free pH Sensing Using Impedance Spectroscopy

Proceedings

Eijkel, Jan¹  Folkertsma, Laura²  Gehrenkemper, Lennart³  Gerritsen, Karin⁴ 

[1] Author to whom correspondence should be addressed.;BIOS-Lab on a Chip Group, MESA+ Institute of Nanotechnology, Technical Medical Centre, Max Planck Center for Complex Fluid Dynamics, University of Twente, 7500 AE Enschede, The Netherlands;Department of Nephrology and Hypertension, University Medical Center Utrecht, 3508 GA Utrecht, The Netherlands;Presented at the Eurosensors 2018 Conference, Graz, Austria, 9–12 September 2018

关键词: pH sensor;    impedance spectroscopy;    conductivity;    indium tin oxide;    double layer capacitance;    human plasma;   

DOI  :  10.3390/proceedings2130742

学科分类：社会科学、人文和艺术（综合）

来源: mdpi

【 摘 要 】

We present a reference-electrode free sensor able to measure both pH and conductivitybased on impedance spectroscopy. The electrode is made of a layer of indium-tin-oxide (ITO). Theimpedance of this electrode at low frequencies depends on its double layer capacity, which varieswith pH due to modification of oxide groups at the ITO surface. At high frequencies, the impedanceis determined by the resistance in the system, which corresponds to the inverse conductivity of thesolution. Because no reference electrode is needed for this technique, miniaturization of the pHsensor is simple. We demonstrate a proof-of-principle experiment of the sensor for human plasmapH measurements.

【 授权许可】

CC BY