The combination of Pb and Ag isotopes in silver coins, artefacts, and ores greatly helps identifying ancient metal sources and detecting alteration such as lead addition, ore mixing, and metal recycling. The present study proposes a new set of procedures suitable for high-precision analysis of lead and silver isotopes in Ag-bearing ores and ancient silver coins. The protocols for combined Pb and Ag extraction and purification are based on multi-step ion-exchange and reversed-phase partition chromatography. In addition to conventional drilling, which irreversibly damages the silver object being sampled, a new method was developed to collect metal from silver coins by etching their edges with a solution of hydrogen peroxide and ammonia (H₂O₂ + NH₄OH), either pure or with added dispersed silicon carbide (SiC) to increase etching efficiency, a technique that only damages the coin patina. This technique can also be applied to silver artefacts other than coins with minor modifications to adapt to different object shapes. Multi-collection inductively-coupled plasma mass spectrometry (MC-ICP-MS) was used to measure the isotopic compositions of both Pb and Ag in ores and coins. Variations in Pb and Ag isotopic compositions are uncorrelated for all the material analyzed, whether ores or silver coins, which demonstrate that isotope variability results from physically different processes. Evidence of mixing between different components is observed for ores, while etched and drilled coins show a conspicuous range of Pb and Ag isotopic compositions. The latter is interpreted as resulting from mass-dependent fractionation during surficial alteration under oxidizing burial conditions, and from patina formation. Silver in patina is isotopically light due to the formation of Ag₂S, while the layer below the patina is isotopically heavy. Preliminary patina removal followed by H₂O₂ + NH₄OH etching with suspended SiC may be used as an alternative to coin drilling when the latter is not possible such as for rare and precious coins. The present techniques will further help distinguish primary Pb isotopic variability in artefacts and coins from secondary variations due to underground interaction with the water table, weathering from prolonged burial, and curatorial handling.

银币，人工制品和矿石中Pb和Ag同位素的结合极大地有助于识别古老的金属来源，并检测出诸如铅添加，矿石混合和金属循环利用之类的变化。本研究提出了一套适用于含银矿石和古银币中铅和银同位素的高精度分析的新方法。铅和银的联合提取和纯化方案基于多步离子交换和反相分配色谱。除了传统的钻孔操作（不可逆地损坏被采样的银物体）外，还开发了一种新方法，可通过用过氧化氢和氨水（H ₂ O ₂  + NH _4）蚀刻银币的边缘来从银币中收集金属。OH），无论是纯净的还是添加了分散的碳化硅（SiC）以提高蚀刻效率的技术，这种技术只会损坏硬币的铜绿。该技术还可以应用于除硬币以外的银制人工制品，并进行了较小的修改以适应不同的物体形状。多次收集电感耦合等离子体质谱法（MC-ICP-MS）用于测量矿石和硬币中Pb和Ag的同位素组成。铅和银同位素组成的变化与所分析的所有材料（矿石还是银币）都不相关，这表明同位素变异性是由物理上不同的过程导致的。在矿石中观察到了不同成分之间混合的证据，而经蚀刻和钻孔的硬币显示出明显的Pb和Ag同位素组成范围。后者被解释为是由于在氧化埋葬条件下的表面变化过程中，质量依赖性的分离以及铜绿的形成。由于银的形成，铜绿中的银同位素轻₂ S，而铜绿下面的层在同位素上很重。当无法进行硬币钻孔时（例如稀有和珍贵的硬币），可以先去除古铜色，再用H ₂ O ₂  + NH ₄ OH进行悬浮SiC刻蚀。本技术将进一步帮助区分伪造品和硬币中的主要Pb同位素变异性与由于地下与地下水位的相互作用，长期埋葬引起的风化以及策展工作而引起的次级变异。