The Application of Potentiometric Methods in Determination Total Organic Carbon Content of Soil

Potentiometric method is one method that is widely used to determine the content of certain ions in a solution, but have not been widely applied to the analysis of soil samples. In this research apply the potentiometric methods for the determination of total organic carbon content of solids affected by oil contamination using CO2 selective electrode as indicator electrode. The principle of the determination of total organic carbon content of the soil is the total organic carbon change into CO2 and subsequently measured concentration of CO2 generated by potential changes electrodes shown by CO2 selective electrode. The concentration of CO2 is obtained proportional to the concentration of total soil organic carbon. Before application for the measurement, the CO2 selective electrode must be characterized. The investigation showed that the response time of the electrode was 3 minutes, limit of detection 5x10-4 M and the optimum pH of the solution was 4 and it was stable for 40 seconds because the CO2 was lost to the air. Total soil organic carbon content of soil was detected in the affected oil stain ranges from 0.05% to 0.01%. For comparison the feasibility of the measurement results, compared with the measurement by titrimetric method. The measurement results of both methods showed that the potentiometric method can be used to determine the total organic carbon content of the soil with the result that a more accurate estimated compared with titrimetric methods.