Modified nano-TiO2 coupled with fluorescence spectroscopy for the separation/analysis of L-tryptophan

A novel adsorbent of carboxymethyl-beta-cyclodextrin modified nanometer TiO2 (CM-beta-CD/TiO2) was prepared and used as a solid-phase extraction (SPE) material coupled to fluorescence spectroscopy determination of L-tryptophan (L-Trp) in biological samples. The experimental conditions for modified nanometer TiO2 separation/preconcentration of L-Trp were optimized. The adsorption capacity of CM-beta-CD/TiO2 for L-Trp was 75.2 mu g. The linear range, detection limit (DL), and the relative standard deviation (RSD) were 0.10-1.20 mu g/mL, 18.8 ng/mL, and 0.67% (n = 3, 1.0 mu g/mL), respectively, with a preconcentration factor of 10. The developed method was applied to determination of L-Trp in real samples and the recoveries were found to be in the range of 99.2-100.3%. For validation, a comparison material of NIC-140686 sample was analyzed and the determined value was in good agreement with the certified value. (C) 2010 Elsevier Inc. All rights reserved.