Breaking down gas chromatography

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Chromatography is the process of separating a mixture into its core components for analysis or reuse. Gas chromatography uses an inert gas as a carrying mechanism within that separation, with samples introduced to the gas and then filtered through a solid distillation column.

Key to the process is the retardation (slowing) of the mixture’s elements in the column, which is achieved by filling the latter with a finely divided inert solid coated with a thin layer of reactive liquid or polymer. The stream of gas passes the coated solid and, while the inert gas – by its very nature – won’t react with it, the additional elements it is carrying will.

Each component doesn’t react with the solid simultaneously, however. This means the sample breaks down over time, with each element leaving the column at a certain point depending on its composition. As such, a mixture of various substances can be split into its constituent parts, allowing each to be quantified, studied and/or filtered.