Fabrication, calibration and evaluation of a phosphate ion-selective microelectrode

To conduct the micro-environment study of flocs in an enhanced biological phosphorus removal (EBPR) process, a phosphate ion-selective microelectrode was developed. The cobalt-based microelectrodes have tip diameters of 5-20 mu m and respond to all the three forms of phosphate ions, namely, H(2)PO(4)(-), HPO(4)(2-), and PO(4)(3-). The calibration curve at pH 7.5 had a slope of 31.5 mV per decade change of concentration and a R(2) value of 0.99. Other characteristics of this microelectrode, such as response time, interferences from pH, ion strength, DO and other anions were also evaluated. (C) 2010 Elsevier Ltd. All rights reserved.