Calibration-free measurement of liquid permittivity and conductivity using electrochemical impedance test cell with servomechanically adjustable cell constant
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Ma-2007-Calibration-Free Mea.pdf
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1005.37 KB
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Author(s)
Ma, Hongshen
Lang, Jeffrey H.
Slocum, Alexander H.
Date Issued
March 2009
Journal
IEEE Sensors Journal
Publisher
Institute of Electrical and Electronic Engineers
Citation
Hongshen Ma, J.H. Lang, and A.H. Slocum. “Calibration-Free Measurement of Liquid Permittivity and Conductivity Using Electrochemical Impedance Test Cell With Servomechanically Adjustable Cell Constant.” Sensors Journal, IEEE 9.5 (2009): 515-524. © 2009 Institute of Electrical and Electronic Engineers
Version
Final published version
Abstract
This paper presents a technique and a device for measuring the permittivity and conductivity of liquids and gases that does not require prior calibration by a reference sample. The technique involves precisely controlling the separation between two closely spaced spherical electrodes to make electrical impedance measurements of the sample media as a function of electrode separation. By leveraging the geometrical accuracy of the spheres and precise control of the electrode separation, the permittivity and conductivity of the sample can be extracted using a simple geometrical model of the electrode. Calibration using a reference sample is replaced by mechanical calibration of the sphere diameter and separation control mechanism, which can be engineered simply and accurately using standard components and processes. The electrode separation is adjusted using a flexure stage and a servomechanical actuator, which enables control of the electrode separation with 0.25 nm resolution with a 50 mum range. Permittivity and conductivity measurements within 1% of established values have been demonstrated.
Subjects
water purity
Calibration-free measurements
permittivity
electrochemical impedance
conductivity
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
http://dx.doi.org/10.1109/JSEN.2009.2015401
