Ionic liquid templated porous nano-TiO2 particles for the selective isolation of cytochrome c

Porous nano-titanium dioxide (TiO(2)) particles with anatase framework were prepared by using an effective template of hydrophobic ionic liquid, i.e., N, N-bis [2-methylbutyl] imidazolium hexafluorophosphate ([PPim][PF(6)]). The nano-TiO(2) particles were characterized with TEM and BET, resulting in the distribution of the pore diameters centering at 7.3 nm and 26.2 nm, attributed to the template effect of the ionic liquid and the aggregation of the TiO(2) particles, respectively. A much improved surface area of 68.31 m(2) g(-1) and a pore volume of 0.2814 cm(3) g(-1) were obtained with respect to 15.16 m(2) g(-1) and 0.0402 cm(3) g(-1) achieved by the non-templated nano-TiO(2) counterpart. The porous nano-TiO(2) particles were used as adsorbent for selective adsorption and isolation of cytochrome c (cyt-c) at certain conditions. An adsorption efficiency of 87% was achieved for 150 microg ml(-1) cyt-c in 1.0 ml of sample solution at pH 9.0 by using 2.0 mg of the nano-TiO(2) particles, in comparison to 30% obtained by the non-templated nano-TiO(2). In addition, an adsorption capacity of 112.6 microg mg(-1) was derived for the porous nano-TiO(2) with respect to 25.1 microg mg(-1) for the normal ones. The absorbed cyt-c could be readily recovered by stripping with a 0.1 mol l(-1) Na(3)PO(4) solution, giving rise to a recovery of ca. 90%. The porous nano-TiO(2) particles have been used for the isolation of cyt-c from human whole blood, achieving satisfactory results by assay with SDS-PAGE.