Comparison of rapid preparation methods for lead isotope analysis of high-lead ceramic glazes

In this research. we identified the provenance of lead flux used in the production of the glaze of unique, high‐quality late medieval stove tiles from the northern part of the Carpathian Basin and elaborated and evaluated a fast preparation process to measure Pb isotope ratios in high‐Pb glazes. A total of 24 stove tiles from seven archaeological sites in present‐day Hungary and Slovakia were analysed. We compared three different methods of preparation to determine the Pb isotopes ratio from high-Pb glazes. Method 1 consisted of the dissolution of bulk chips of glaze, dilution of the solution and mass spectrometric analysis without Pb purification. Method 2 collected a tiny amount of glaze material from the surface with acid‐impregnated swabs, subsequent dilution and direct analysis of the sample solution. Method 3 used solutions from method 1, extraction of Pb by ion‐exchange chromatography and analysis of the purified Pb. Each preparation method produced similar Pb isotope ratios. Results demonstrate that the Pb isotope ratios are independent of the preparation methods. Therefore, we recommend using the simplest method of surface sampling of high-lead glazes with swabs (method-2). It is a fast procedure that requires less effort in the laboratory with the benefit of preserving the integrity of cultural heritage objects. The majority of the Pb isotope ratios fall into one group and shows a strong overlap with the lead ore deposits of the Krakow-Silesia mining region. The imported Pb was used not only in the liquation process to separate silver from the copper ore mined in the territory of the Slovak Ore Mountains, but also in the preparation process of the glazes of most of the stove tiles analysed that were produced in the region. The lead ore locally mined in the Slovakian Ore Mountains may have been used, possibly mixed with Pb derived from Poland, only for the green glazes of some Csábrág/Čabraď and Ipolyság/Šahy tiles. The Pb isotope ratios of some of the tiles excavated in Eger are similar to the Pb isotope data of the Triassic Bleiberg‐type Pb‐Zn ore deposits, indicating a potential use of lead imported from Austria.