How fast does the probe respond?
The probe response is limited by the speed of diffusion of oxygen into the sensor. Our standard films are very fast (<1 second) in gases and slightly slower in liquids. In viscous samples, the diffusion through the sample will determine the response rate. The probe will respond quickly in samples such as water, and more slowly in viscous samples such as oils, emulsions and creams. Unlike an electrode, the optical sensor will not consume oxygen. This means that stirring the sample will increase the response rate, but will not affect the final equilibrium reading. Also, optional probe overcoatings, applied to exclude ambient light and improve chemical resistance, will slow probe response to 20-30 seconds in gases and 30-50 seconds in liquids.
