A novel imprinted TiO2 nanoparticles were synthesized via a sol-gel process using L-tryptophan(L-Trp) as temple molecules and TiO2 nanoparticles as imprinted matrix.The imprinted TiO2 nanoparticles were investigated by scanning electron microscopy and infrared spectroscopy.The result indicated that L-Trp was imprinted into TiO2 nanoparticles successfully.Appropriate template cavities in TiO2 nanoparticles were formed after the template molecules were removed by treatment with 1% ammonia solution.Fluorescence spectrophotometry was used to study the separation abilities of L-Trp and D-tryptophan(D-Trp) in the imprinted TiO2 nanoparticles.The results showed that imprinted TiO2 nanoparticles had a high selectivity to L-Trp,and the separation factor was 2.42 under the optimum molar ratio of L-Trp to titanium precursor(1∶0.2) in pH 6.0 solution.