Sähkönjohtuvuuskammio

Sähkönjohtuvuuskammio, often translated as conductivity cell or cell constant cell, is a device used in analytical chemistry to measure the electrical conductivity of a liquid solution. It consists of two or more electrodes, typically made of inert material like platinum, housed within a container or probe. The electrodes are separated by a fixed distance, defining a specific volume.

The principle of operation relies on Ohm's law and the fact that ions in a solution can carry electrical current. When a voltage is applied across the electrodes, ions in the solution migrate towards the oppositely charged electrodes, creating an electrical current. The magnitude of this current is directly proportional to the concentration of ions in the solution and therefore its conductivity.

The cell constant (K) is a crucial parameter for conductivity cells. It is a geometrical factor that accounts for the electrode dimensions and their separation. The measured conductance (G), expressed in siemens (S), is related to the specific conductivity (κ) of the solution by the equation κ = G * K. Specific conductivity is usually expressed in siemens per meter (S/m) or siemens per centimeter (S/cm).

Conductivity cells are widely used in various applications, including water quality monitoring, industrial process control, and chemical analysis. They are essential for determining the purity of distilled or deionized water, monitoring the concentration of electrolytes in solutions, and assessing the effectiveness of desalination processes. Calibration of the conductivity meter and cell with standard solutions is vital for accurate measurements. Different cell designs exist, varying in electrode material, configuration, and temperature compensation mechanisms, to suit specific measurement requirements and environmental conditions.