ChemPharma - Centrifuge
In a centrifuge, a suspension is spun at high speed, separating the molecules based on their mass. The purity of the centrifugate must of course be checked, but the presence of organic solvents and the rotation at high speed creates a risk of explosion. This is why the centrifuge's "headspace" is filled with nitrogen. In this nitrogen blanket, the oxygen concentration must be measured continuously to ensure safety.
By sending a light beam (IR light) through the liquid and measuring its transmission or absorption, you can measure its clarity or turbidity. The particles present block some of the light.
A compact optical oxygen sensor is easy to install and takes up little space. Of course, the sensor itself is explosion-proof.