Abstract: The present invention relates to a system for detecting, in a reliable, precise and highly sensitive manner, biochemical agents such as enzymes that catalyze a redox potential change. One electrode is used to measure redox potential changes in an aqueous electrolyte containing the biochemical agents. Another electrode is used to deliver a feedback current to the electrolyte in response to measured Changes in electrolyte redox potential. The amount of feedback current or charge delivered through the electrode to the electrolyte is sufficient in magnitude to maintain a constant redox potential. Quantitation of the amount of feedback current or charge necessary to maintain the constant redox potential may then be used to determine the amount of biochemical agents present. Alternatively, the redox potential need not be kept constant, but instead may be allowed to reach a new steady-state.

Abstract: A reference electrode for use in measuring electrochemical corrosion potential and pH of, for example, water in a drum boiler at supercritical temperatures and which is corrosive includes an alumina or zirconia tube which is packed with a bulk solid electrolyte. The electrolyte consists of a mixture of silver chloride and glass in an optimally 2 to 4 weight ratio or glass particles with silver chloride precipitated around each particle. A solidified silver chloride electrode interfaces with the bulk electrolyte and has embedded in it a conductive silver electrode which provides the electrical contact. Use of the foregoing provides an immobilized solid electrolyte which displays stability and integrity as the temperature and pressure cycles between extremes.