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

Abstract

Porous nano-titanium dioxide (TiO2) particleswith anatase framework were prepared by using an effective template of hydrophobic ionic liquid, i.e.,N, N-bis [2-methylbutyl] imidazolium hexafluorophosphate ([PPim][PF6]). Thenano-TiO2 particles were characterized with TEM and BET, resulting in thedistribution of the pore diameters centering at 7.3 nm and 26.2 nm, attributedto the template effect of the ionic liquid and the aggregation of theTiO2 particles, respectively. A much improved surface area of 68.31 m2 g − 1 and a pore volume of0.2814 cm3 g − 1 were obtainedwith respect to 15.16 m2 g − 1 and 0.0402 cm3 g − 1 achieved bythe non-templated nano-TiO2 counterpart. The porous nano-TiO2 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 µg ml − 1 cyt-c in 1.0 ml of sample solution at pH 9.0 by using 2.0 mg of the nano-TiO2 particles, in comparison to 30% obtained by the non-templated nano-TiO2. In addition, an adsorption capacity of 112.6 µg mg − 1 was derived forthe porous nano-TiO2 with respect to 25.1 µg mg − 1 for the normal ones. The absorbed cyt-c could be readily recovered by stripping with a 0.1 mol l − 1 Na3PO4 solution, giving rise to a recovery of ca. 90%. The porous nano-TiO2 particles have been used for the isolation of cyt-c from human whole blood, achievingsatisfactory results by assay with SDS-PAGE.