Isosbestic point

Isosbestic point in the bromocresol green spectrum. The spectra of basic, acid and intermediate pH solutions are shown. The analytical concentration of the dye is the same in all solutions.

In spectroscopy, an isosbestic point is a specific wavelength, wavenumber or frequency at which the total absorbance of a sample does not change during a chemical reaction or a physical change of the sample. The word derives from two Greek words: "iso", meaning "equal", and "sbestos", meaning "extinguishable".[1]

  1. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "isosbestic point". doi:10.1351/goldbook.I03310