What can be measured with a DO400 Fiber Optic Oxygen Sensor?
Oxygen partial pressure (pO2, mmHg) and temperature of an aqueous or gaseous sample can be directly measured; oxygen concentration (mg/L, ppm, and mM) and percent saturation (%AIR and %O2) are calculated based on oxygen solubility at known pO2, temperature, salinity, and pressure. Oxygen partial pressure is actually the Oxygen Activity (or called Fugacity). No mater using an optical sensor or an electrochemical sensor, the directly measurable parameter is always the oxygen activity, i.e., partial pressure. At the same oxygen partial pressure, its oxygen concentration (mg/L or mM) can vary depending on the temperature and salinity, since those two parameters will affect the solubility of oxygen in water.
