Lead isotope ratios in lead-glazed ceramics determined by laser ablation multi-collector inductively coupled plasma mass spectrometry for discriminating purpose

Abstract

Herein, the potential of laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) for the determination of Pb isotopes of lead-glazed ceramics has been investigated. To obtain good precision and accuracy, thallium was adopted to correct mass bias during Pb isotope analyses. The average ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁶Pb, and ²⁰⁸Pb/²⁰⁶Pb ratios determined by LA-MC-ICP-MS were within 0.027% of that obtained by the solution nebulizer MC-ICP-MS (SN-MC-ICP-MS). The homogeneity of lead isotope distribution expressed as the 2RSD range was from 0.013% to 0.022% for ^206,207,208Pb/²⁰⁴Pb and from 0.006% to 0.013% for ^207,208Pb/²⁰⁶Pb. These values were 10 times lower than those obtained by LA-ICP-MS with a dynamic reaction cell (DRC) and sufficient to classify the lead-glazed ceramics into 6 groups in this study. On the other hand, accurate and precise lead isotopic compositions could be obtained by the LA-MC-ICP-MS technique after non-matrix-matched standard calibration. Additionally, two lead-glazed ceramics could potentially serve as quality control samples, or even external calibration standards, for in situ lead isotope analyses of ancient lead-glazed materials. The proposed method is a promising tool for the analysis of archaeological ceramics rich in Pb due to negligible (ng level) sample damage, high spatially resolved isotopic information, rapidity (approximately 10 min per sample), and non-matrix-matched calibration.