Dictionary > Beer-Lambert law

Beer-Lambert law

Definition
noun
The principal law in spectrometry in which it states that the absorbance at a given wavelength of light is proportional to the molar extinction coefficient, the concentration of absorbers in the sample of the molar solution, and the length of the light path
Supplement
According to the Beer-Lambert law, the absorbance at a given wavelength of light (A) is proportional to the molar extinction coefficient (E), the concentration of absorbers in the sample of the molar solution (C), and the length of the light path (L), thus, the equation, A = ECL. Or, simply put, the concentration of a substance in moles is proportional to the absorption of a given wavelength of light by a solution of the substance. It is regarded as the principal law in spectrometry1, and is used in the study of spectroscopy.
The law was discovered by Pierre Bouguer and attributed to Johann Heinrich Lambert. August Beer extended the exponential attenuation law by including the concentration of solutions in the attenuation coefficient.2
Also called:

  • Lambert–Beer law
  • Beer–Lambert–Bouguer law

See also:

  • spectrometry
  • Molar absorption coefficient
  • Extinction coefficient
  • Molar absorptivity
  • Molar extinction coefficient
  • Molar absorbancy index
  • Reference(s):

    1 Svanberg, S. (2004). Atomic and molecular spectroscopy : basic aspects and practical applications. Berlin New York: Springer.

    1 Beer (1852) “Bestimmung der Absorption des rothen Lichts in farbigen Flüssigkeiten” (Determination of the absorption of red light in colored liquids), Annalen der Physik und Chemie, vol. 86, pp. 78–88.


    You will also like...

    Lake Wakatipu, New Zealand
    New Zealand’s Unique Geographical History

    Explore why New Zealand has such unique flora and fauna, and learn why long periods of geographical isolation. This less..

    Photosynthesis and respiration
    Plant Metabolism

    Plants are responsible for incredible feats of molecular transformation. Plant processes, such as photosynthesis, photop..

    "Opabinia regalis"
    The Evolutionary Development of Multicellular Organisms

    Multicellular organisms evolved. The first ones were likely in the form of sponges. Multicellularity led to the evolutio..

    Muscle
    Muscle

    Muscle cells are specialized to generate force and movement. Learn about the different types of muscle tissues in this t..

    Circulation
    Circulation

    The circulatory system is key to the transport of vital biomolecules and nutrients throughout the body. Learn about the ..

    green leaf - close up view
    Leaves

    Leaves are the major photosynthetic organ of a plant. Apart from that, they are also crucial to water movement. In this ..