The influence of fluorescence concentration quenching on the emission anisotropy of flavins in glycerine-water solutions.

The measurements of the emission anisotropy r/r0 of flavomononucleotide (FMN) within a range of concentrations of 10(-5)-10(-1) mol/L in glycerine-water solutions of different viscosities--0.056 Pa/s (system I) and 0.256 Pa/s (system II) have been carried out. In the range of high concentrations the repolarization effect due to the sharp drop of the quantum yield has been observed. The experimental results have been compared with theoretical expressions evaluated by taking into account both concentration and rotation depolarization. A good agreement on the values of the theoretical parameters obtained from independent measurements has been found. It has been stated that in the investigated systems the excitation energy transfer may be treated as a Markov process.