Mesoporous TiO2 based optical sensor for highly sensitive and selective detection and preconcentration of Bi(III) ions

The optical chemosensor technology demands to design a single, preconcentrator based sensing system having higher sensitivity, sufficient selectivity and efficient removal of metal ions with simple operating and recognition methodology. Here we successfully designed mesoporous TiO2,based sensing system which can be utilized as "naked eye" colorimetric sensor with simultaneous removal of the Bi(III) ions in a single step by strong interaction between TiO2 and [Bi(DZ)(3)] complex. This is explained by the small particle size (10 nm) and large surface area (174 m(2)/g) of mesoporous TiO2, which plays an important role in terms of accessibility and adsorption amount of [Bi-(DZ)(3)] complex. The designed sensing system shows high sensing ability even at trace level concentration of Bi(III) ion suggesting easier flow of Bi(III) ion over a wide range of concentrations. The detection limit for Bi(III) ions is estimated to be similar to 1 ppb. One of the major advantages of current sensing system is the selective sensing performance up to 5000 times higher concentration of interfering cations and anions than that of Bi(III) ions. This novel approach provides a new route for simultaneous detection and removal Bi(III) ions in a single step and can be a time and cost alternative tool for environmental safety. (C) 2014 Elsevier B.V. All rights reserved.