Infrared reflection-absorption spectroscopic (IRAS) measurements are reported for acetone and acetonitrile dosed onto Pt(lll) in ultrahigh vacuum (uhv) both in the presence and absence of adsorbed potassium atoms at 90 K with the objective of elucidating the nature of cation solvation and its influence on surface-solvent interactions at these model electrochemical interfaces. Corresponding variations in the metal-uhv work function (Phi) evaluated with a Kelvin probe yield additional insight into the interfacial electrostatic environment as a function of the alkali and solvent exposure. Acetone and acetonitrile are particularly suitable solvents with which to evaluate the involvement of the surface on interfacial ion solvation, since both interact specifically with Pt(lll), In both cases, chemisorption gives rise to vibrational signatures which are clearly distinguishable from those of the "bulk-like" multilayers, associated in particular with carbonyl (nu(C=O)) and C=N stretching (nu(C=N)) vibrations.