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Denoting the wavelength of light at which two related compounds have identical extinction coefficients; for example, the wavelength at which the absorption spectra of hemoglobin and oxyhemoglobin cross is their isosbestic point. Spectrophotometry at that wavelength measures total concentration of hemoglobin, regardless of the extent to which it might be oxygenated.
[Ger. isosbestisch, fr. G. isos, equal, + sbestos, extinguished]
References in periodicals archive ?
2+]-induced quenching of fura-2 fluorescence was estimated at 360 nm excitation wavelength (F360), which represents the isosbestic wavelength and is not sensitive to the changes in the [[Ca.
Furthermore, spectroscopic titration studies for the interaction of these food additives with DNA showed that these dyes bind to calf thymus DNA and distinct isosbestic points are observed clearly suggesting binding of the dyes to DNA.
Fura-2 fluorescence was alternately excited at the isosbestic point (357 nm) and at the calcium-sensitive wavelength (.
A separate measurement at an isosbestic point (815 nm for hemoglobin), a wavelength at which the absorption coefficients of the two species are equal, provides the total amount of reduced and oxidized forms, which is proportional to blood volume.
Overlapping the absorbance spectra for mixtures of ITX and MA having differing irradiation times between 0 and 60 min showed that a single isosbestic point was produced at approximately 350 nm (Fig.