Voltmetria

Voltmetria is an analytical technique used to measure the potential difference between two electrodes in an electrochemical cell, providing insights into the concentration of ions or the redox properties of a sample. It is a fundamental method in electroanalytical chemistry, often employed alongside other techniques such as potentiometry and voltammetry. The primary instrument used in voltmetria is the voltmeter, which quantifies the voltage generated by an electrochemical reaction under controlled conditions.

In basic voltmetria, a reference electrode (such as the silver-silver chloride or calomel electrode) and a working electrode (e.g., a platinum or glass electrode) are immersed in a solution containing the analyte. The potential difference between these electrodes is measured while maintaining a constant current or under varying conditions. This approach is particularly useful in potentiometry, where the measured potential correlates with the concentration of ions via the Nernst equation.

Voltmetria can be applied in various fields, including environmental monitoring, biomedical analysis, and industrial quality control. For instance, it is used to determine the pH of solutions by measuring the potential of a glass electrode relative to a reference electrode. Additionally, it plays a role in studying redox reactions, where the oxidation-reduction potential of a species is determined by its electrochemical behavior.

The technique offers high sensitivity and selectivity, making it suitable for trace analysis. However, factors such as electrode contamination, temperature fluctuations, and solution composition can influence accuracy, requiring careful calibration and experimental design. Modern voltmeters often integrate digital processing and automated data acquisition, enhancing precision and reproducibility in measurements.