In I/GCSE Chemistry, we will learn about gas chromatography .
Gas chromatography
- Separates complex mixtures
- Measures how much of the chemical is present (quantitative)
- Detects chemicals that are present in the mixture, but in small quantities the harmful chemical is a contaminant.
Refer to I/GCSE Chemistry, In this case the:
- MP = un-reactive gas aka. Carrier gas
- SP = viscous liquid e.g. oil
Process
1. Carrier gas supplies the MP which travels through a column.
2. Down the column there is an oven. Part of the column is placed in the oven. The hole where you insert the mixture (via a syringe) is located in the oven section.
3. The oven makes the chemicals in the mixture/sample turn into gas b/c of the high heat.
If you alter the oven temperature, you can separate your compounds because they have different boiling points.
4. The carrier gas is now travelling to the oven section where it mixes with the sample.
5. The gases travel to the column which is packed with SP.
The column is long, thin, coiled and sealed
6. The chemicals in the gas are distributed between the phases
7. The chemicals travel up the column and go through the detector
8. The detector sends signals to a recorder/computer every time a compound is identified
Interpreting chromatograms
When it comes to I/GCSE Chemistry,
Retention time: How long it takes the compound to pass the column
Peak height: Shows how much of the compound was present
You got it now!
