. "Aanderaa 4831F oxygen optode"@en . . . "accepted"@en . . "AA optode 4831F" . "AA optode 4831F"@en . . "SDN:L22::TOOL1240" . "A dissolved oxygen sensor which provides analogue (0-5V) and digital output (RS-232) to third party data loggers, gliders and floats. Measurement based on the ability of selected substances to act as dynamic fluorescence quenchers. The fluorescent indicator is a special platinum porphyrin complex embedded in a gas permeable foil that is exposed to the surrounding water. This sub-model is not equipped with a black optical isolation coating that protects the complex from sunlight and fluorescent particles in the water. This sensing foil is attached to a window providing optical access for the measuring system from inside a watertight housing. The foil is excited by modulated blue light, and the phase of a returned red light is measured. For improved stability the 4831 optode also performs a reference phase reading by use of a red LED that does not produce fluorescence in the foil. This sub-model is fitted with a fast response (transparent) sensing foil (response time <8 secs). By linearizing and temperature compensating, with an incorporated temperature sensor, the absolute O2 concentration can be determined. Accuracy +/- 1.5% or 2uM; precision +/- 0.2 uM."@en . . . . . . . . . .