CORROSION OF PLATINUM-ELECTRODES IN PHOSPHATE-BUFFERED SALINE SOLUTION

A high sensitive detection method allows the direct determination of P t2+/Pt4+ within a concentration range of ng/l (ppt). The procedure was used to establish the development of soluble platinum species during constant or dynamic polarisation of platinum electrodes in phosphate b uffered saline solution. Platinum showed some properties of a passive metal. In the passivated state the dissolution was influenced by a sur face film. Furthermore a soluble platinum species was found to be prod uced during the reduction of the surface oxide. These results confirme d by direct evidence the conclusions of earlier investigations concern ing the corrosion of platinum based on electrochemical measurements.