Planar REDOX and Conductivity
for ISS Water Quality Measurements
Martin G. Buehler1, Gregory M. Kuhlman1 , Didier Keymeulen1, and Samuel P. Kounaves2
1. Jet Propulsion Laboratory
2. Department of Chemistry. Tufts University
Bare-metal based REDOX and conductivity sensors that are used to detect ionic species in solution by measuring the electrochemical cell current as the voltage is scanned. The simplicity and robustness of these sensors allows their use in the analysis of ionic species found in natural and drinking water. The measurements include 1) conductivity measurements which provide a gross indication of the ion concentrations present in solution, 2) Cyclic Voltammetry (CV) which provide a survey of electroactive species, and 3) Anodic Stripping Voltammetry (ASV) which allow ion identification and quantification. The ions detected are Zn, Fe, Pb, Cu, and Ag and the methodology for their extraction is discussed. Also discussed is the dependence of ASV results on the deposition time and voltage scan rate. This paper also describes the construction of the sensors, the potentiostat electronics, the measurement methodology, and applications to water quality measurements.