[A study on the effect of rare earth metal ions on fluorescence spectra of the tryptophan using fluorescence spectroscopy].

Rare earth metal ions and tryptophan form ion-association complex in basic medium. The complex causes fluorescence quenching of tryptophan. Fluorescence emission of tryptophan and quenching caused by rare earth metal ions both reach a climax in H3BO4-HAc-H3PO4-NaOH at pH 10 to 11, and all rare earth metal ions have the approximate effects on fluorescence quenching of tryptophan. The molecular mode of complex of rare earth metal ions and tryptophan has been founded and mechanism of fluorescence quenching has been studied in this paper.