Chemical Analysis

Question 1

how does paper chromatography work?

Answer 1

To separate food colourings and other artificial elements, the colouring you want to test is put on filter paper and placed in a cup with some solvent and is left, as time goes on and the solvent moves further up the paper the dyes move and separate in different places. In some however there are only certain spots visible this does not mean that they are the only ones present they are the minimum there

Question 2

what are the advantages of using machines?

Answer 2

1. Very sensitive - can detect even the tiniest amount of substances
2. Very fast and tests can be automated
3. Very accurate

Question 3

how does gas chromatography work? (7 steps)

Answer 3

1. A gas is used to carry a substance through a column packed with a solid material
2. The substances travel through at different speeds, so they are separated
3. The time they take to reach the detector is called the retention time, which can be used to identify the substances
4. The recorder draws a gas chromatograph. The number of peaks shows the number of different compounds in the sample
5. The position of the peaks show the retention time of each substance
6. The gas chromatography column can be linked to a mass spectrometry. This process is known as GC-MS and can identify the substances leaving the column accurately
7. To work out the molecular mass of each substance from the graph it draws, you just read it off the molecular ion peak