TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The material for catalyzing the dissociative absorption of oxygen is platinum. The solid state oxygen anion conductor is gadolinium doped ceria or yttria stabilized zirconia. The reference oxygen environment is a solid-state source of oxygen from a metal/metal oxide couple such as copper (Cu)/Cu (I) oxide (Cu2O) or palladium (Pd)/Pd oxide or a metal oxide/metal oxide couple such as Cu2O/Cu (II) oxide.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Component: A mechanism is provided for controlling the temperature of the cell. It comprises a heater (22) and a thermocouple arrangement (24). A mechanism is provided for controlling the oxygen electrochemical semi-permeability of the cell to control the sensitivity of the sensor to the introduction of the organic contaminant molecules. The oxygen electrochemical semi-permeability control mechanism comprises an additional electrode in the reference environment (20) and a mechanism for controlling the rate of flux of oxygen anions flowing between the additional electrode and the measurement electrode. The oxygen electrochemical semi-permeability control mechanism comprises a mechanism for controlling the electrical current flowing between the additional electrode and the measurement electrode. A mechanism is provided for controlling the amount of oxygen within the monitored environment. A mechanism is provided for drawing a flow of gas into the monitored environment, and a mechanism is provided for extracting oxygen from gas being drawn into the monitored environment.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Material: The material for catalyzing the dissociative absorption of oxygen is platinum. The solid state oxygen anion conductor is gadolinium doped ceria or yttria stabilized zirconia. The reference oxygen environment is a solid-state source of oxygen from a metal/metal oxide couple such as copper (Cu)/Cu (I) oxide (Cu2O) or palladium (Pd)/Pd oxide or a metal oxide/metal oxide couple such as Cu2O/Cu (II) oxide.