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

A novel adsorbent of carboxymethyl-beta-cyclodextrin modified nanometer TiO(2) (CM-beta-CD/TiO(2)) 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 TiO(2) separation/preconcentration of l-Trp were optimized. The adsorption capacity of CM-beta-CD/TiO(2) for l-Trp was 75.2 microg/g. The linear range, detection limit (DL), and the relative standard deviation (RSD) were 0.10-1.20 microg/mL, 18.8 ng/mL, and 0.67% (n=3, 1.0 microg/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.