The solvent effects on the fluorescent properties of fluorometric determination of Sc with morin was investigated. In the presence of organic solvents, the sensitivity and selectivity of fluorescent reaction were greatly increased, e.g. the fluorescent quantum yield of Sc-morin complex and Sc-morin-n-PrOH are 0.056 and 0.325, resp. A highly sensitive fluorescent method for determination of Sc was proposed in the presence of n-PrOH. Beer's law was obeyed for 0-13 mg Sc/25 mL in the Sc-morin-n-PrOH system. The interference of foreign ions was studied. Satisfactory results were obtained in the determination of trace Sc in rare earth samples. The molar ratio of Sc:morin is 1:3. The solvation no. of n-PrOH is 3. The enhancement of fluorescent quantum yield of Sc-morin complex was decreased with the organic solvents in the order of n-PrOH > iso-PrOH > tert-BuOH > acetone > dioxane > EtOH > MeOH > DMSO > H2O. The solvation nos., stability constants of the complexes, and the spectra were determine for the studied solvent systems.

Key words: FLUORIMETRIC ANALYSIS, SOLVENTS, MONOCARBOXYLIC ACID, ORGANIC COMPOUNDS, ACETONE, ALCOHOL, SCANDIUM, ANTIPYRINU, FLUORESCENCE CHARACTERISTIC, MORIN