Re-Usable-Sensor (SUS) in Single-Use PolarWell
Hamilton manufactured for years the OxyFerm polarographic oxygen sensor. CerCell manufacture and install optionally (before bagging and E-beam irradiation) the non-invasive transparent Polycarbonate tube / Silicon membrane named PolarWell.
In real life the user inserts their own DO Re-Usable-Sensor (RUS) into the non-invasive PolarWell Single-Use-Well (SUW). And fasten gently, tighten slightly by hand until 0,5 Nm torque. There is no direct contact between the sensor tip and the media, broth. No autoclaving of OxyFerm is required insuring the sensor obtain a long and stable lifetime. PolarWell for the OxyFerm is available in PG 13.5 x 120, 220, 320 sizes.
The polarographic sensor principle is invented by Prof Leland Clark early 1960ties. The sensor electrode tip is isolated from the broth by a thin Silicone (originally Teflon) membrane. The membrane is permeable to molecular oxygen and allows this gas to reach the cathode, where it is electrolytically reduced. The reaction is diffusion limited and depends strongly on the permeability properties of the membrane and by the oxygen gas concentration, which is the measured quantity.