The aim of this paper is to characterize materials belonging to one of the masks coming from the Lord of Ucupe's tomb in the region of Lambayeque in Peru. The mask belongs to the Moche culture which lived in the north of Peru since 100 CE. Along with the study of the extraordinary metal alloy technique using X-ray fluorescence (ED XRF) integrated with the Monte Carlo simulation, this paper investigates the blackish material used as an adhesive for its inlaid eyes. This material was analysed through the ATR FT-IR and characterized through Py-GC/MS and GC/MS for the organic components and SEM-EDS for the inorganic components. The chemical characterization of the adhesive material coming from this type of artefact, based on our knowledge of current literature, is the first on this material and allows us to take a further step into the understanding of the constituents used for this purpose.