Lyoluminescence of glutamine, serine, arginine · HCl, lysine · HCl, inositol and mannose has been investigated. It has been demonstrated that the commercial origin of the sample plays an important role in the LL response. Recrystallization enhances the LL signal of the less sensitive mannose samples and reduces the dispersion of LL yields. Differences resulting from the nature and concentration of radiation-induced free radicals and from the grain size distribution cannot explain the LL variability and the change of LL yield after recrystallization. Supposed effects of water or solvent retention and traces of impurities are discussed.
