μ-XRF analysis of glasses: a non-destructive utility for cultural heritage applications

Abstract

This paper presents a μ-XRF analytical approach for a non-destructive study of Cultural Heritage glass finds. This technique can be used for quantitative analysis of small volumes of solid samples, with a sensitivity that is superior to the electron microprobe but inferior to an ICP-MS system. An experimental set-up with natural and synthetic glass standards is proposed here for the quantitative analyses of major and trace elements on glass objects which cannot be sampled such as small archaeological or historical artefacts from Cultural Heritage. The described method, performed by means of the commercial μ-XRF Eagle III-XPL, was applied to Islamic glass specimens of Sasanian production (III-VII century A.D.) previously analyzed by ICP-MS and SEM-EDS techniques (P. Mirti, M. Pace, M. Negro Ponzi and M. Aceto, Archaeometry, 2008, 50(3), 429-450; P. Mirti, M. Pace, M. Malandrino and M. Negro Ponzi, J. Archaeol. Sci., 36, 1061-1069; and M. Gulmini, M. Pace, G. Ivaldi, M. Negro Ponzi and P. Mirti, J. Non-Cryst. Solids, 2009, 355, 1613-1621) and coming from the archaeological site of Veh Ardasir in modern Iraq. Major elements (Na, Mg, Al, Si, K, Ca, Fe) of glass specimens show an accuracy better than 5%. Trace elements (Cr, Mn, Sr and Zr) display an accuracy better than 5% when the checked elements have a concentration >100 ppm by weight, whereas it is around 10% with a concentration <100 ppm by weight. μ-XRF is, therefore, a suitable elemental analysis technique for the non-destructive study of small glass finds due to its relatively good accuracy, reproducibility and low detection limits (∼tens ppm).