Time-dependence of fluorescence signals during reaction

7 Time-dependence of fluorescence signals during reaction 

Taking into account that the concentrations of reactants vary with time and more than one reactant can fluoresce, eq. (S.107) has to be written in a more generalised form 

By the variation of fluorescence intensity over the spectral range of the fluorescence spectra, the so-called spectral fluorescence distribution resembles the variation of fluorescence intensity with observation wavelength. This fai is similar to used in absorption spectroscopy. 

The above equations give a correlation between the measured fluorescence intensity and the concentration of one or more reactants. As discussed in Section 1.3.2 this fluorescence intensity depends on the photophysical properties of the reactants and on the measurement set-up. Since in fluorescence spectroscopy no reference measurement is possible, the measured intensity will give a relative value dependent on the geometry, reflectivity, and absorption in the solution. 

To reduce the dependence on the geometric properties in fluorescence spectroscopy usually very dilute solutions are used. The photokinetic factor F(t) is approximated according to eq. (5.111). Under these conditions neither the change in absorbance at the wavelengths of irradiation E nor changes in the factors r(E ) and r(E ) have to be taken into account. Thus eq. (5.136) can be rewritten as 

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