Unsupported platinum nanoparticles (PtNPs) (similar to 12 nm in diameter) were synthetized by the polyol method and ultraviolet-visible spectroscopy (UV-vis), scanning electron microscope (SEM), and X-ray powder diffraction (XRD) characteristic of their agglomerates were examined. Then, three pyridine alpha-aminophosphinic acid isomers (alpha-,beta-, and gamma-) were synthetized and assembled on the surface of PtNPs. Differences in adsorption and thus, in the spectral response resulting from positional isomerism, were checked by surface-enhanced Raman scattering (SERS) at 785 nm excitation wavelength. The manner of interaction of the investigated isomers with PtNPs were discussed and compared. General conclusions were drowned. (C) 2017 Elsevier B.V. All rights reserved.