LUMOGALLION ADSORPTION IN THE POLAROGRAPHIC-DETERMINATION OF SOME IONS

It is demonstrated that Lumogallion exhibits polarographic activity an d yields one or two peaks in a chronoamperogram, depending on the pH o f the buffer supporting solution. The main peak has the shape of an is osceles triangle; this fact, along with other diagnostic features, sug gests its adsorption nature. The reduction of Lumogallion is irreversi ble because of adsorption. With increasing pH, the potential of the ma in peak shifts from -0.42 to -0.71 V. The current of reduction of Lumo gallion is proportional to its concentration in the range 1 X 10(-5)-1 .2 X 10(-4) M at pH 4.2. The following Lumogallion adsorption paramete rs have been calculated: attraction factor, adsorption constant, maxim um adsorption, and surface area occupied by an adsorbed particle. A nu mber of metal ions yield sensitive chronoamperograms in the presence o f Lumogallion. The copper chronoamperogram is of most interest. It is shown that copper can be determined in the presence of Fe(III), Co(II) , Ni(II), and Cd(II).