Representatives of five classes of optically active compounds have been adsorbed at chiral single crystal Pt electrodes in order to assess the structural and other requirements for chiral/chiral molecular recognition in adsorption and in possible subsequent electro-oxidation. In some cases, analogous studies have been made using achiral stepped and flat Pt surfaces. Cyclic voltammetry in 0.1 M sulphuric acid, which reveals the presence of terraces, steps and kinks at the Pt surface, has been used to follow adsorption as a function of surface geometry and to detect electro-oxidation. For the alkaloids cinchonidine and codeine, and various aromatic compounds possessing chirality in the side-chain (including ephedrine) indiscriminate adsorption occurred at comparable rates at kinked, stepped, and flat surfaces; a proportion of the Pt remained exposed at maximum coverage due to the nature of the random ad-layer. Adsorption of anions of R,R-tartaric acid caused a shift to negative potential of the hydrogen underpotential features and the I I I I I anion feature of the cyclic voltammograms, showing that tartrate ions were more strongly adsorbed than sulphate and bisulphate ions. Adsorption of R- and S-2-chloropropanol, R- and S-2-butanol, R-1,3-butanediol, and 2R,3R- and 2S,3S-butanediol was accompanied in each case by significant oxidation currents in the double layer potential range, indicating that electro-oxidative adsorption had occurred. However. both the magnitudes of the currents and the potentials at which maximum current was observed were independent of the chirality (R- or S-) of the Pt surfaces. This contrasts with the enantioselective response observed when D- and L-glucose were adsorbed at R- and S-Pt(3 2 1). The requirements for chiral recognition in adsorption appear to be (i) the dissociative adsorption of a weakly adsorbed precursor with the chiral surface and (ii) a geometry which is favoured by the adsorbate having a cyclic structure or containing an aldehyde moiety adjacent to a stereogenic centre. The importance of molecular sticking probability and/or adsorption enthalpy is also discussed. It is concluded that as the sticking probability approaches unity or the adsorption enthalpy becomes large relative to the difference in adsorption energy between R- and S-kinks. enantioselective effects will become more and more obscured. (C) 2004 Published by Elsevier B.V.