Solid-matrix luminescence analysis: photophysics, physicochemical interactions and applications

Solid-matrix luminescence spectrometry (SMLS) has become an established approach for the trace analysis of organic compounds, and more recently, for several inorganic species. A rather large amount of photophysical data has been obtained from lumiphors adsorbed on solid matrices. However, these data have not been compared nor discussed in detail. In this review, fluorescence quantum yields and phosphorescence quantum yields for several lumiphors adsorbed on solid matrices are considered. Also, a number of solid-matrix luminescence quantum yield values are compared to solution quantum yield values. Both fluorescence and phosphorescence lifetimes are contrasted for lumiphors on solid matrices and lumiphors in solution. Several fundamental photophysical equations are presented. The discussion centers around how the equations can be used to calculate basic photophysical rate constants for compounds adsorbed on solid matrices. Photophysical rate constants for fluorescence and phosphorescence and intersystem crossing are compared in some detail. Several recent advances in physicochemical interactions are considered in light of recent data. The importance of rigidity in SML, the effects of moisture and gases in SML, the effects of heavy atoms in SML, the role of the heat capacity in SML, and other parameters are discussed. Recent applications, with emphasis on solid-matrix phosphorescence (SMP), are also presented. (C) 1997 Elsevier Science B.V.