Fabrication of anodically electrodeposited iridium oxide film pH microelectrodes for microenvironmental studies.
A new method for fabrication of anodically electrodeposited iridium oxide film pH microelectrodes has been developed in this study. Novel for its tip size (3-10-microm tip diameter), the microelectrode is fabricated in a tapered glass micropipet filled with a low melting point alloy. The tapered end is recessed and platinized. Thereafter, iridium oxide is electrodeposited over the platinized end in the recessed part. The microelectrode has a very short response time (t80 < 5 s) in the pH range of 0-12 with an accuracy of 0.05 pH unit. The pH microelectrode is not affected by most ions and complexing agents of relevance in environmental and biological studies; it can be used in fluids over wide ranges of stirring speeds (0-55 rpm) and temperatures (approximately 5-40 degrees C). Redox agents such as dissolved oxygen and hydrogen peroxide have no effect on the pH response while quinhydrone, ferro- and ferricyanide, and sodium sulfide have marked effects. However, the microelectrode can still be used in any sample when calibration is done in standards having similar redox characteristics.
Bezbaruah
Achintya N
AN
Civil Engineering Department, University of Nebraska-Lincoln at Omaha, Omaha, Nebraska 68182-0178, USA.
Zhang
Tian C
TC
D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007495:Iridium / Q000737:chemistry*; D008839:Microelectrodes; D036103:Nanotechnology; D010984:Platinum; D013696:Temperature
D007202:Indicators and Reagents; C044458:iridium oxide; D007495:Iridium; D010984:Platinum