Some Techniques in Polarography

The basic polarographic circuit and its accuracy is discussed. A bridge-type current amplifier, using one transistor, is presented as one solution to the problem of displaying the very small current flow in a polarographic circuit. A second solution, the insertion of a pH-millivoltmeter directly into the basic control circuit, is evaluated from the medical worker´s viewpoint. Techniques and circuits employing four different types of pH-millivoltmeters are described. The direct application of a polarographic cell for continuous measurement of the oxygen partial pressure in the blood of a heartlung machine is presented.