The surface chemistry of TiO₂ as well as the powerful adsorption capability of the nanometre material was used to separate inorganic chromium species in this work. When the pH of the sample solution is lower than the isoelectric point of TiO₂, its surface is positively charged and anions of Cr(VI) can be adsorbed; on the contrary, the surface is negatively charged and cations of Cr(III) can be caught. Maximum adsorption rates of 34.5% and 95.4% for Cr(VI) at pH 3 and Cr(III) at pH 6 were obtained, respectively. Possible adsorption mechanisms were discussed considering the surface chemistry of TiO₂ and the coordination chemistry of Ti, O and Cr. A simple and automated chromium speciation method was therefore developed using flow injection minicolumn separation and electrothermal atomic absorption spectrometric detection (ET-AAS). The adsorption and elution were incorporated in a flow injection program for selective preconcentration of Cr(III) or Cr(VI). As a result, no extra oxidizing/reducing process was necessary for an automated chromium speciation analysis. Factors influencing adsorption and elution of inorganic chromium species were carefully investigated. Detection limits as low as 0.01 µg L⁻¹ for Cr(VI) and 0.006 µg L⁻¹ for Cr(III) were achieved. The proposed method is highly sensitive and selective for inorganic chromium speciation analysis of drinking water.