The dynamic response of optical oxygen sensors and voltammetric electrodes to temporal changes in dissolved oxygen concentrations
نویسندگان
چکیده
Accurately measuring dissolved oxygen concentrations in fresh and salt water environments has long been an interdisciplinary priority. Many methodologies exist, including two very promising new ones, optical fluorescence quenching optrodes (or optodes) and solid-state voltammetric electrodes. In this study we compare the responsiveness of these two techniques to dynamic changes in dissolved oxygen concentrations, using traditional methods of polarographic oxygen sensors and Winkler’s chemical titrations to corroborate the measurements. Advantages of the optrode system include simplicity of operation and high sensitivity when changes in oxygen concentrations are small (< 10 M O2 min−1). Advantages of voltammetry include equally high sensitivity, independent of rate of change of oxygen concentration, and the capability of simultaneously measuring other chemical species. Both systems have the capability of producing high-resolution, continuous oxygen profiles by collecting and reporting real-time data. Kinetic estimates of the binding and dissociation constants for the ruthenium–oxygen complex in the optrode revealed a relatively long half-life of the Ru2+–O2 complex for dissociation (t1/2 of 43.2 s to equilibrate from a 100 to 0% O2 saturation change). In contrast, the Ru2+–O2 association constant was 5.0 times faster (t1/2 of 8.6 s to equilibrate from a 0 to 100% O2 saturation change). Therefore, because of these differential kinetics, researchers should take care when using a ruthenium-based optrode to measure real-time dissolved oxygen concentrations undergoing temporal variability. © 2004 Published by Elsevier B.V.
منابع مشابه
ساخت و بررسی عمل کرد سنسور اکسیژن و بهبود آن با استفاده از نیمه هادی اکسید فلزات تیتانیوم و سزیم و قلع به عنوان مرجعهای جامد
We report the development of different types of oxygen sensors based on yittria-stabilized zirconia (YSZ) as a solid electrolyte. The conventional oxygen sensor is a concentration cell with two porous Pt electrodes, one of which is exposed to air as a constant (reference) oxygen concentration and the other is exposed to automobile exhaust gas of variable oxygen concentration, depending on the a...
متن کاملEffect of different oxygen levels on growth performance, stress response and oxygen consumption in two weight groups of great sturgeon Huso huso
In the present study, different oxygen levels were examined in two weight groups of great sturgeon Huso huso including small size (with initial weight 280.9 ± 49.2 g) and large size (with initial weight 1217.9 ± 138.1 g). The fish were kept in hypoxia (2-3 mg/l), normoxia (5-6 mg/l) and hyperoxia (9-10 mg/l) conditions for 8 weeks and then were individually placed in the tanks with oxygen lev...
متن کاملEffect of different oxygen levels on growth performance, stress response and oxygen consumption in two weight groups of great sturgeon Huso huso
In the present study, different oxygen levels were examined in two weight groups of great sturgeon Huso huso including small size (with initial weight 280.9 ± 49.2 g) and large size (with initial weight 1217.9 ± 138.1 g). The fish were kept in hypoxia (2-3 mg/l), normoxia (5-6 mg/l) and hyperoxia (9-10 mg/l) conditions for 8 weeks and then were individually placed in the tanks with oxygen lev...
متن کاملModeling and optimization of oil refinery wastewater chemical oxygen demand removal in dissolved air flotation system by response surface methodology
In this present study the dissolved air flotation (DAF) system was investigated for the treatment of Kermanshah Oil Refinery wastewater. The effect of three parameters on flotation efficiency including of flow rate (outflow from the flotation tank), saturation pressure and coagulant dosage on chemical oxygen demand (COD) removal was examined experimentally. All the experiments were done under a...
متن کاملDevelopment of Advection-Dispersion Model of Dissolved Oxygen Using Numerical Solutions
Urban and industrial wastewaters are considered as the most contaminant of surface water. Entrance of these pollutants to the river reduces the concentration of dissolved oxygen and aquatic life will be threatened. So, one of the main qualitative characteristics of water resources management is the concentration of dissolved oxygen. The base of the developed model in this investigation is t...
متن کامل