Polarography is an electroanalytical technique used to determine the concentration of metal ions in a given sample. It is based on the principle of measuring the current produced by the reduction or oxidation of metal ions at a working electrode usually a dropping mercury electrode as a function of the applied potential. The resulting current-potential curve, known as a polarogram, can be used to determine the concentration of the metal ion in the sample.To accurately determine the concentration of a metal ion using polarography, follow these steps:1. Prepare a series of standard solutions containing known concentrations of the metal ion of interest.2. Measure the polarograms of the standard solutions and the sample solution.3. Plot the current peak height as a function of the concentration of the metal ion for the standard solutions to obtain a calibration curve.4. Determine the concentration of the metal ion in the sample solution by comparing its current peak height with the calibration curve.Several factors may affect the accuracy of the analysis in polarography:1. Temperature: Temperature variations can affect the diffusion coefficient of the metal ion, leading to changes in the current response. It is essential to maintain a constant temperature during the analysis.2. Supporting electrolyte: The presence of a suitable supporting electrolyte is crucial to maintain a constant ionic strength and minimize the competition between the metal ion and other ions in the sample.3. Interfering substances: The presence of other electroactive species in the sample may cause overlapping or shifting of the peaks, leading to inaccurate results. In such cases, separation techniques like ion exchange or solvent extraction can be employed to isolate the metal ion of interest.4. Electrode surface: The cleanliness and condition of the electrode surface can significantly affect the accuracy of the analysis. It is essential to clean and polish the electrode regularly to ensure a reproducible response.5. Stirring: Adequate stirring of the sample solution is necessary to maintain a uniform concentration of the metal ion near the electrode surface. Inadequate stirring can lead to inaccuracies in the measured current.By considering these factors and optimizing the experimental conditions, polarography can be used to accurately determine the concentration of metal ions in a given sample.