We
analyzed a red paint sample from the surface of a gold mask
excavated from a Middle Sicán elite tomb in Peru. The mask
covered the face of the principal male and dates from ca. 1000 AD,
a period when many painted precious metal objects were produced. The
paint’s inorganic pigment was identified more than 30 years
ago as cinnabar (a mercuric sulfide scarlet-red to brown-red mineral),
but the identity of the effective organic binder remained a mystery.
Fourier transform infrared (FTIR) analysis of the sample indicated
a proteinaceous composition, and no lipids were recovered from an N,O-bis(trimethylsilyl)trifluoroacetamide
(BSTFA) derivatized extract of the sample analyzed by gas chromatography–mass
spectrometry (GC-MS). Proteomics analysis by nanoLC-MS/MS identified
unique peptides in the sample, which were matched to human blood and
bird egg proteins via Uniprot database searches. These included immunoglobulin
heavy chain, immunoglobulin G, serum albumin, and ovomucoid. Cinnabar-based
paints were typically used in the context of social elites and ritually
important items. The presence of human blood would support previous
ideas that red cinnabar paint may represent “life force”
intended to support “rebirth”. As the red paint sample
came from the first scientifically excavated Sicán gold mask,
the results suggest a method to authenticate similar unprovenanced
masks now in private and museum collections. Proteomics data set identifier .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.