Gas Chromatography Basics

Gas Chromatography Overview

• The mobile phase in gas chromatography is an inert gas, commonly helium or nitrogen, which helps transport the sample through the system.
• Gas chromatography is especially effective for separating and analyzing gases like methane (CH4) and carbon dioxide (CO2).
• The stationary phase in gas-liquid chromatography (GLC) consists of a liquid coated on an inert solid support, allowing interaction with the solutes.

Separation Mechanisms

• In gas-solid chromatography (GSC), solutes exhibit different affinities for the stationary phase, primarily due to adsorption; a stronger affinity leads to slower movement through the column.
• Gas chromatography separates components in a sample through a combination of partitioning and vaporization, with differing interactions in the stationary phase causing separation of compounds.

Liquid Chromatography Facts

• The mobile phase in liquid-solid chromatography (LSC) moves through a stationary phase composed of a solid, which may interact with solutes differently based on their affinity.
• In a specific type of chromatography, the stationary phase is chemically bonded and permanently fixed to a porous solid; this enhances stability and consistency during analysis.
• In liquid chromatography, particularly in GLC, the stationary phase is a liquid that remains on a solid support as a thin film, optimizing separation efficacy.

Additional Chromatography Characteristics

• A unique type of chromatography utilizes a mobile phase that is moderately polar, neither fully polar nor nonpolar, which can help in separating a broader range of analytes based on their polarity properties.