A graphical correction procedure for inner filter effect in fluorescence quenching titrations

Abstract

Inner filter effects constitute a serious limitation for fluorescence quenching titrations with absorbing ligands. In most cases, the conventional methods employed for correction of such effects yield reliable results only at low total absorbance and, hence, titration is often restricted to relatively low ligand concentrations. To attain accurate corrections also in samples of elevated absorbance, a simple procedure based on graphical extrapolation has now been developed. The new method extends the accessible range of absorbance by nearly one order of magnitude and was successfully applied in the determination of the dissociation constants of the complexes of creatine kinase with MgADP and MgATP.