Luminescent method for determining low concentrations of a substance in optically dense media

We have developed a method for quantitative luminescent analysis of multicomponent media. To carry out this method, we need to use a standard luminescent probe and have overlap between the luminescence excitation spectra of the probe and the analyte substance. We have shown that the method is applicable for analysis of scattering media with different absorption optical densities, including optically dense media. We have demonstrated that it is invariant relative to changes in the experimental geometry and the parameters of the medium. A broad range of measurable values is characteristic of the method. Its sensitivity is determined by the sensitivity of the luminescence intensity measurements. We have determined concentrations of organic substances in the range ~10^–10 to 10^–11 g/cm³.