The sorption of Na + and Cl - electrolyte ions from an aqueous solution onto single crystal TiO 2 has been the subject of an investigation using XPS in combination with in situ cryogenics. In particular the samples were decontaminated from adventitious carbon by annealing at 600 o C prior to the exposure to aqueous solution. Further, the subsequent transfer of the sample to the spectrometer was performed in a liquid nitrogen filled hollow sample holder in order to preserve the chemistry and structure at the sample surface. The presence of an ionic layer consisting of H 2 O, Na + and Cl - has been confirmed using angular dependent XPS, where the electrolyte ions are distributed in at least 2-3 monolayers.