Hi,
This article was cited from http://www.explainthatstuff.com/chromatography.html at 30 Dec 2016. As long as surfed on the Internet, this link was very simple to describe about how gas chromatography work.
Here's a very simplified overview of what happens in the gas chromatography process:
- The eluant (carrier gas) is introduced from a gas cylinder outside the machine. It's called the carrier because that's exactly what it does—carry the sample we're studying through the machine. In gas chromatography, the carrier gas is the mobile phase.
- The rate of flow of the carrier is carefully controlled to give the clearest separation of the components in the sample.
- The carrier enters the machine through an inlet port/splitter.
- The sample being measured is injected into the carrier gas using a syringe and instantly vaporizes (turns into gas form).
- The gases that make up the sample separate out as they move along the column (orange), which is the stationary phase. The column is a very thin (capillary) tube, sometimes as much as 30–60m (100-200ft) long, coiled and entirely contained inside an oven (blue) that keeps it at a high enough temperature to ensure that the sample remains in gas form. The temperature of the oven can be carefully controlled.
- As the sample separates out and its constituent gases travel along the column at different speeds, a detector senses and records them. Various different detectors can be used, including flame ionization detectors, thermal conductivity detectors, and mass spectrometers (usually separate machines).
- The data analyzer/recorder attached to the machine draws a chromatogram (chart) with peaks corresponding to the relative amounts of the different chemicals in the sample.