Wave height - Concentration plots (calibration/working plots):

Standard solutions of variant concentrations of ions under investigation are prepared using the similar supporting electrolyte and 0.005% maximum suppresser (say gelatin) and polarograms are drawn along with the known concentrations of ions. Wave heights of all known concentrations are noted down and after making correction for residual current a plot is drawn as function of concentration (calibration curve). Keeping the supporting electrolyte and gelatin as above, polarogram of unknown is also recorded keeping temperature constant at 25°C. The wave height of this unknown is referred to the working curve and its concentrations is noted

Figure: Calibration plot