- The differential pulse polarographic analysis of a mixture of indium and cadmium in 0.1MHCl is complicated by the overlap of their respective voltammograms. The peak potential for indium is at 0.557 V and that for cadmium is at 0.597V. When a 0.800ppm indium standard is analyzed, ip is 200.5 at 0.557V and 87.5 at 0.597V. A standard solution of 0.793ppm cadmium has ip of 58.5 at 0.557V and 128.5 at 0.597V. What is the concentration of indium and cadmium in a sample if ip is 167.0 at 0.557V and 99.5 at 0.597V