A method to measure carbon solubility limit in Rh is proposed based on dissolution of surface carbon. Achieving of the solubility limit gives rise to a new surface phase: graphene islands, which can be easily registered by surface sensitive methods, like Auger spectroscopy and thermionic emission. The method can be applied to a platinum metal which does not produce a bulk carbide, and contains carbon in a form of bulk solid solution. The carbon solubility limit in Rh was found by the equation log(n(Lim) [at.%]) = 2.2 - 4600/T (K) for the temperature range 1200-1800 K. (C) 2014 Elsevier B.V. All rights reserved.