Advantages of an Electrochemical Ion Analyzer for ISS Water Monitoring

Minimizing or eliminating the requirement for launching, storing and using hazardous solutions to carry out certain analytical procedures (i.e., water quality monitoring) would have a positive impact on in-flight operational efficiency and safety. We have developed a compact reagentless ion analyzer that features: (i) on-demand generation of acid and base from a benign salt solution; (ii) demonstrated the use of an electrochemical cell that operates as a high pressure pump with no moving parts; (iii) combined microengineered fluid management and sample handling through the use of a stackable components fabricated from light weight polymeric materials, and (iv) developed a compact system design that permits parallel processing and analysis of cations and anions. Through use of an electrochemical cell, salts from the waste stream can be efficiently recovered and reused in a cyclic fashion that significantly minimizes resource consumption. The suitability of the system design for monitoring ions in the sub-ppm range will be discussed using examples such as ammonia, nitrate and nitrite. In addition, the potential for expanding the use of electrochemical cells as acid/base generators to support other types of in-flight analytical and test procedures will be overviewed.