Kapillaarikolonnit

Kapillaarikolonnit, also known as capillary columns, are a fundamental component in gas chromatography (GC). They are narrow, open tubes, typically made of fused silica or stainless steel, with inner diameters ranging from 0.1 to 0.53 millimeters. The inner wall of these columns is coated with a stationary phase, which is a liquid or solid material designed to interact with the components of the sample being analyzed.

The principle of separation in a capillary column relies on the differential partitioning of analytes between the mobile phase (an inert carrier gas, such as helium or nitrogen) and the stationary phase. As the carrier gas pushes the vaporized sample through the column, components that interact more strongly with the stationary phase will move slower, while those that interact less will travel faster. This difference in migration speed leads to the separation of the sample into its individual components as they elute from the column at different times.

Capillary columns offer significant advantages over older packed columns, including higher resolution, improved sensitivity, and faster analysis times. Their narrow diameter allows for a greater number of theoretical plates per unit length, leading to sharper peaks and better separation of closely related compounds. The thin film of stationary phase also contributes to faster mass transfer, reducing band broadening and enhancing efficiency. Consequently, capillary columns are the standard for most modern GC applications in fields like environmental monitoring, pharmaceuticals, and food analysis.