The exchange regime involving isotopologues of a single chemical compound has the advantage of being exclusively entropy driven, i.e. the composition of the equilibrium state is known a priori and is unobscured by varying the chemical affinities of the exchanging thiols with respect to the metal surface . Additionally, since the reduced masses are different between isotopologues, the vibrational fingerprints change accordingly as a result of the isotopic shift. Vibrational spectroscopy thus becomes an obvious choice for the method of study of the exchange between isotopologues. Surface-enhanced Raman scattering (SERS) spectroscopy is particularly appropriate, as the signal acquired with this method originates mainly from the monolayer directly adsorbed onto the plasmonic surface, while the molecules located at a greater distance experience enhancement smaller by orders of magnitude . This relatively short probing range along with extremely high sensitivity and quantitative analysis capability make SERS technique particularly advantageous for that application.