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A Summary of Spectroscopy Techniques

Type	Features	Uses
Flame Tests	inexpensive fast, but some colours may be masked by others making it unreliable qualitative technique limited application as many common metals (e.g., Al & Mg) do not colour a flame a type of emission spectroscopy which can be observed by the naked eye or by using a spectroscope to see a series of bright lines	Identification of metals in some salts Li⁺ crimson Na⁺ yellow K⁺ lilac Ca²⁺ brick red Sr²⁺ scarlet Ba²⁺ green Cu²⁺ green-blue

Colorimetry	relatively inexpensive fast, requiring a set of standard solutions qualitative & quantitative a type of absorption spectroscopy limited to coloured solutions or compounds	copper (II) sulfate in garden sprays iron (III) concentration using KSCN to form the coloured Fe(CNS)²⁺ complex coloured solutions such as food colourings
Colorimetry	wavelength of light is selected for maximum absorbance & a calibration curve is constructed of absorbance versus concentration

Atomic Absorption Spectroscopy (AAS)	expensive fast, requiring a set of standard solutions quantitative a type of absorption spectroscopy that can be used for all metals and metalloids (semi-metals)	mercury in shellfish lead in soil samples trace metals in mineral waters
Atomic Absorption Spectroscopy (AAS)	correct hollow cathode tube selected & a calibration curve constructed of absorbance versus concentration. (solutions may have to be diluted)

UV-visible spectroscopy	expensive fast, requiring a set of standard solutions qualitative & quantitative a type of absorption spectroscopy limited to coloured solutions or compounds	concentration of some coloured pharmaceuticals in blood serum concentration of metal ions using coloured complexes concentration of food colourings
UV-visible spectroscopy	wavelength of light selected for maximum absorbance and a calibration curve constructed of absorbance versus concentration