Report your findings on your datasheet. Your introduction should explain what the Hill reaction is, why it can be measured using an artificial electron acceptor, and what you specifically set out to do. Results should include a table showing the raw data, a graph in which the A600 is plotted as a function of time, and a few sentences explaining why you performed the experiment, where the data are presented, and describing the major trends observed. Your discussion should explain the results obtained with each tube. To demonstrate oxygen evolution we will use an oxygen electrode.
Oxygen electrodes measure oxygen concentrations by polarography.
The electrode consists of a platinum cathode and a silver anode in contact with a small amount of saturated KCl. A polarizing voltage is imposed across the electrodes and oxygen arriving at the surface of the platinum cathode is reduced by electrons driven by this polarizing voltage. The net result is flow of electrons around the circuit, and the amount of current generated is proportional to the oxygen concentration at the surface of the platinum cathode. To prevent leakage of the KCl, the electrodes and KCl solution are located behind a membrane which is impervious to polar compounds but which oxygen can cross freely. We can then measure oxygen concentration in a solution by placing this membrane in contact with the solution.