Calibration and use of a Clark-type oxygen electrode from 5 to 45 degrees C

A calibration procedure for a Clark-type oxygen electrode over a wide range of temperatures is described. The autoxidation of duroquinol (2,3,5,6-tetramethyl-1,4-benzenediol) was used to verify the electrode's ability to accurately sense the total amount of dissolved O2 in an aqueous buffer. Electrode response time was measured by using oxygenated ethanol to deliver a rapid increase in O2 concentration to the reaction medium. An oxygen-producing system (spinach thylakoids) was utilized to test the range of O2-evolution rates able to be sensed. It was concluded that a Clark-type oxygen electrode has the absolute sensitivity, rapidity, and range necessary to accurately track rates of O2 production or consumption from 5 to 45 degrees C.