Photoluminescence spectra in polycrystals of chirally pure and racemic phases of tryptophan

The photoluminescence spectra of three crystalline phase modifications of aromatic amino acid tryptophan are compared: the left phase of L-tryptophan, the right phase of D-tryptophan, and the racemic phase of DL-tryptophan. The photoluminescence spectra were recorded using a fiber-optic procedure, a small-size FSD-8 spectrometer, and a data processing system that enables comparison of the analyzed spectrum with the spectrum of a reference substance. Photoluminescence was excited by a pulsed-periodic ultraviolet laser at a wavelength of 266 nm.