Although its molar absorptivity ( extinction coefficient ) is relatively low, PI exhibits a sufficiently large Stokes shift to allow simultaneous detection of nuclear DNA and fluorescein-labeled antibodies, provided the proper optical filters are used.
12.
Where ? is wt . % of the species of interest within the sample; A is the absorbance of the species; M is the molar mass ( in g mol " 1 ); ? is molar absorptivity ( in L mol " 1 cm " 1 ); l is sample thickness ( in cm ); ? is density ( in g mol " 1)
