Phosphorescence Spectra and Analyses of Some Indole Derivatives.

Phosphorescence spectra of solutions frozen and at low temperatures (77 degrees K) possess more characteristic structure and detail than fluorescence spectra. They contain no background due to scattering of the exciting radiation. Thus greater analytical specificity and sensitivity are obtained. Some indole derivatives indistinguishable by spectrofluorimetry are easily differentiated by spectrophosphorimetry.