Polarographic analysis for corticosteroids: Part 1. The electroanalytical properties of corticosteroids

The electroanalytical behaviour of corticosteroids has been studied in different supporting electrolytes. The reduction patterns are established by examining pH profiles, by constant-potential coulometry, fast-sweep voltammetry, potentiometry with ion-selective electrodes and differential pulse polarography. Dimerization and alcohol formation take place with the reduction of the C-3 keto group resulting in one or two peaks, depending on the number of double bonds in the A-ring and the pH. The C-20 keto group is reduced to an alcohol. Both reduction steps can be used for analytical purposes. The differential pulse peak height is linear with the concentration down to 10-6 M steroid.