Comparison of pXRF and LA-ICP-MS analysis of lead-rich glass mosaic tesserae

•Comparison of surface analysis by pXRF with LA-ICP-MS analysis of high lead glass.•Relatively low lead concentrations adversely affect analysis of glass by pXRF.•Separate calibrations for low- and high-lead glasses effective in correcting data.•EPMA-WDS and LA-ICP-MS data reported for nine standards not previously available. Handheld (portable) X-ray fluorescence spectrometry (pXRF) allows for fast, in situ surface analysis, however, its application in archaeological research requires substantial optimisation. This paper investigates the matrix effects of high lead glass on the experimental results of pXRF in comparison to laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) data. 289 archaeological glass mosaic tesserae with varying lead concentrations up to 35 wt% PbO were systematically analysed by both techniques. In addition, thirteen reference glasses were analysed, including nine glass standards (BGIRA1-6 and AD1-3), which were not previously reported. The detection of low Z elements (Ca and above) was inaccurate in both low- and high-lead tesserae, due to a shallow depth of analysis and suboptimal surface conditions of archaeological glass. The presence of relatively low concentrations of lead (