Potensimetri

Potensimetri, also known as potentiometry, is a technique used in analytical chemistry for the determination of an analyte concentration without the need for calibration standards. It is based on the measurement of the potential difference between two electrodes in a solution, which is proportional to the logarithm of the analyte concentration. The technique is particularly useful for the analysis of ions in solution, such as hydrogen ions (pH), and can be applied to a wide range of analytes, including metal ions, redox-active species, and gases.

The basic principle of potentiometry involves the use of a reference electrode and an indicator electrode. The reference electrode has a stable and well-defined potential, while the indicator electrode responds to the analyte of interest. The potential difference between the two electrodes is measured using a high-impedance voltmeter, and the resulting potential is proportional to the logarithm of the analyte concentration. This relationship is described by the Nernst equation, which relates the potential difference to the analyte concentration, temperature, and other factors.

Potentiometry is a versatile and widely used technique in analytical chemistry, with applications in environmental monitoring, clinical analysis, and industrial process control. It is particularly useful for the analysis of samples with high ionic strength, where other techniques may be less effective. However, potentiometry has some limitations, including the need for careful electrode selection and maintenance, and the potential for interference from other ions in the sample. Despite these limitations, potentiometry remains an important tool in analytical chemistry, providing a simple and reliable method for the determination of analyte concentrations.