Analysing Substances

Paper Chromatography
1. works because some compounds dissolve better than others in particular solvents
  1. Their solubility determines how far they travel up the paper
2. to do this you need to use the same solvent at the same temperature
Instrumental Analysis
1. Advantages
  1. they are highly accurate and sensitive
  2. They are quicker
  3. They enable small samples to be analysed
2. Disadvantages
  1. is usually very expensive
  2. Takes special training to use
  3. Gives results that can often be interpreted by comparison with data from known substances
3. Compounds in a mixture can be separated by gas chromatography
  1. Once separated, compounds can be identified using a mass spectrometer
    1. The mass spectrometer can be used to find the relative molecular mass of a compound from its molecular ion peak
  2. compounds with stronger attractions take longer to travel through the column = longer retention time
Additives are added to foods to improve its appearance/ improve taste/ how long it will keep
1. Food scientists can analyse foods to identify additives

Resource summary

	Created by emilywebber98 almost 11 years ago