LIBS utilization for the elemental analysis of black resin and gold used by ancient Egyptians in embalming

Laser-induced breakdown spectroscopy (LIBS) has recently been considered one of archaeology's most preferred analytical techniques because of its simplicity; it does not need sample preparation, is fast, is a quasi-nondestructive analytical technique, and is cost-effective. Besides, LIBS can perform stratigraphic measurements, which are of significant interest in cultural heritage samples. Such pros facilitate utilizing LIBS in situ, e.g., in museums and excavation sites. In the present work, LIBS has been used to analyze black resin remains and gold fragments used in mummification and collected from the Ptahemwia tomb in the vicinity of Djoser's Step Pyramid at Sakkara. The IR (1064 nm) and the UV (355 nm) laser wavelengths have been used in the LIBS measurements. The results revealed both samples' emission line intensity dependence on the laser wavelength. In this regard, elements such as Na, Ca, Mo, and CN (molecular band) for black resin and Au, Ag, and Cu for gold samples were detected as significant elements. It has been found that the detection sensitivity achieved by the LIBS technique was higher when using the UV laser. This is crucial in detecting rare earth elements REE (Y, La) and/or minor elements (Nb, Zr) in the samples under study. Furthermore, the energy-dispersive X-ray (EDX) analysis has been used to validate the LIBS results for the same samples. In agreement with what is reported in the literature, the LIBS and the EDX spectroscopic results showed that the black resin investigated in the present study is bitumen in its composition. (c) 2024 Consiglio Nazionale delle Ricerche (CNR). Published by Elsevier Masson SAS. All rights reserved.