Atomic absorption spectrometers (AA) use the absorption of light to measure the concentration of gas-phase atoms

Spectrometers are analytical instruments which disperse an emission (such as particles or radiation) according to some property of the emission (such as mass or energy) in order to measure the amount of the dispersion.

Atomic emission and optical emission spectrometers determine analyte concentration via a quantitative measurement of the optical emission from excited atoms

Mass spectrometers separate ions by their mass-to-charge (m/z) ratios.

Infrared (IR) spectrometers measure the wavelength and intensity of the absorption of infrared light by a sample

UV and visible spectrometers measure the amount of ultraviolet (UV) and visible light transmitted or absorbed by a sample placed in the spectrometer

Raman spectrometers are used to measure the wavelength and intensity of inelastically scattered light from molecules.