From Bioblast
Description
If a sample contains a number of absorbing substances, it is sometimes possible to select discrete pairs of wavelengths at which the change in absorbance of a particular substance (due to oxidation or reduction, for example) is largely independent of changes in the absorbance of other substances present. Dual wavelength analysis can be carried out for cytochrome c by subtracting the absorbance at 540 nm from that at 550nm in order to give a measure of the degree of reduction. Similarly, by subtracting the absorbance at 465 nm from that at 444 nm, an indicator of the redox state of cytochrome aa3 can be obtained.
MitoPedia methods: Spectrophotometry