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ab·sor·bance (A, A),(ab-sōr'bants),
AbsorbanceChemistry A logarithm of the percent transmission of a wavelength of light through a liquid.
Microbiology A measure of the amount of light absorbed by a suspension of bacteria or an organic solution, measured by spectrophotometry. Absorbance values are used to plot the growth of bacteria in broth and gauge the purity and concentration of molecules in solution.
absorbancea spectrophotometric measurement of the light absorbed by a solution at a particular WAVELENGTH. The absorbance (A) derives from the percentage of light transmitted as follows:
where Io is the incident light intensity and I is the transmitted light intensity. The absorbance is related to the molar absorption coefficient (extinction coefficient) e (cm-1M-1), concentration c (M), and path length l (cm) as follows:
Absorbance is sometimes referred to as OPTICAL DENSITY, although this term should be used for measurement of light scattering.