Phosphorescence quenching of L(-)-tryptophan in dimethyl sulfoxide at 77 K by trivalent lanthanide ions

Quenching of the corrected phosphorescence emission of tryptophan in dimethyl sulfoxide by trivalent lanthanide ions Ln3+ can be interpreted in terms of a static model leading to triplet quenching constants ranging from 1.3 x 101 to 9.1 x 101 M-1. These values increase with increasing spectral overlap and J values of the ground state of the appropriate lanthanide ions. The phosphorescence lifetime of tryptophan is virtually independent of [Ln3+] and has a value of 6.15+-0.25 s, in agreement with the static model of triplet quenching. (Auth.)