Global Analysis of Kinetic and Stationary Diffusion-Mediated Fluorescence Quenching Data

Abstract

The recovery of the Smoluchowski-Collins-Kimball (SCK) model parameters from simulated kinetic and stationary diffusion-mediated fluorescence quenching data is studied. A Levenberg-Marquardt least-squares optimization routine was used for the estimation of the sum of the diffusion coefficients of the fluorophore and quencher, D ) D F* + D Q , the sum of their radii, R ) R F* + R Q , and the intrinsic quenching rate coefficient k. Single-curve analysis leads to rather poor parameter estimates. Global, i.e., simultaneous, analysis of quenching decays with different time resolutions () channel widths) improves the recovery. The best results are obtained when quenching decays are analyzed globally with stationary Stern-Volmer data. The intrinsic quenching rate coefficient k can be recovered when quenching decays are measured with sufficiently high number of counts at a peak channel and analyzed globally with stationary Stern-Volmer data.