Determination of chemical composition of pottery from antic Siscia by ICP-AES after enhanced pressure microwave digestion

Abstract

This study describes the results of chemical characterization of archaeological pottery excavated at Sisak, Croatia known as prehistoric town Segestica (IV–I century BC) or Siscia, the capital of Roman province Pannonia Savia (I–IV century AD). Chemical composition of pottery shards and a sample of raw clay material was determined by ICP-AES analysis after high pressure microwave digestion. High efficiency of the applied system allows decomposition of ceramics by the use of nitric acid exclusively. All shards excavated from prehistoric, Early-Roman and Roman strata were decomposed without additional load of hydrofluoric acid. The accuracy of the performed procedure was tested by certified reference materials of medium and high silica content. The obtained results of sixteen element concentrations were in good agreement with certified values. Measured concentrations of main, minor and trace elements were subjected to univariate and multivariate statistical analyses. Based on principal component analysis and clustering of data, a grouping of samples in four clusters was established. The results of chemical analysis of ceramic products were found to be comparable to archaeological interpretation that denotes differentiation between local production and imported goods.