Active Potentiometry for Dissolved Oxygen Monitoring with Platinum Electrodes

Abstract

Potentiometric oxygen monitoring using platinum as the electrode material was enabled by the combination of conventional potentiometry with active prepolarization protocols, what we call active potentiometry. The obtained logarithmic transfer function is well-suited for the measurement of dissolved oxygen in biomedical applications, as the physiological oxygen concentration typically varies over several decades. We describe the application of active potentiometry in phosphate buffered salt solution at different pH and ion strength. Sensitivity was in the range of 60 mV/dec oxygen concentration; the transfer function deviated from logarithmic behavior for smaller oxygen concentration and higher ion strength of the electrolyte. Long-term stability was demonstrated for 60 h. Based on these measurement results and additional cyclic voltammetry investigations a model is discussed to explain the potential forming mechanism. The described method of active potentiometry is applicable to many different potentiometric sensors possibly enhancing sensitivity or selectivity for a specific parameter.

Review of Dissolved Oxygen Detection Technology: From Laboratory Analysis to Online Intelligent Detection

“…In this method, a platinum electrode was polarized at the anode and cathode, which improved the problem of a long electrode balance time [85]. Peter realized dissolved oxygen detection through a combination of conventional potentiometry with active pre-polarization protocols, with a sensitivity within the range of 60 mV/dec oxygen concentration [86].…”

Measuring and regulating oxygen levels in microphysiological systems: design, material, and sensor considerations

“…[165][166][167][168] Potentiometric sensors for dissolved oxygen at physiologicallyrelevant oxygen concentrations have been most recently demonstrated by Zimmermann et al, but they do not demonstrate any operation in a cell culture system. 162 It should be noted, oxygen concentrations were measured from 0.1-228 μM, but their measurements significantly deviated from the classical Nernstian logarithmic transfer function (Eq. 1); therefore, potentiometry measurements in liquid phase systems may have to consider alternative models during operation.…”

“…159,160 While potentiometric measurement of gaseous oxygen, potentiometric measrument of dissolved oxygen is emerging as a potential alternative. 161,162 For this review, we will focus on the more common amperometric measurement techniques, but we will briefly discuss the principles and emerging benefits of potentiometric measurement of dissolved oxygen. Equilibrium potential measurements enable oxygen measurement via the Nernst Equation (Equation 1), where E (Volts) is the potential difference of the electrochemical cell, E 0 , is the potential of the reduction or oxidation reaction or the standard potential, R is the gas constant (mol −1 •K −1 ), F is Faraday's constant (C•mol −1 ), T is temperature (K), n is the number of electrons active in the reaction, and [O 2 ] is the dissolved oxygen concentration (mol•L −1 ).…”

A galvanic-based dissolved oxygen level monitoring sensor system in freshwater ponds

“…Zimmermann dkk. [16] menyadari deteksi oksigen terlarut melalui kombinasi potensiometri konvensional dengan protokol pra polarisasi aktif, dengan sensitivitas dalam kisaran konsentrasi oksigen 60 mV/dec. Kajian mengenai perakitan sensor DO telah dilakukan dengan berbagai metode.…”