A procedure for the determination of Pb isotope ratios by coupling liquid chromatography to a multicollector ICP-MS has been developed. The procedure allows the direct injection of samples after dissolution without resorting to time-consuming off-line separation procedures. The separation of Pb from concomitant elements is carried out by anionic exchange as ethylenediamine tetraacetic acid (EDTA) chelates using EDTA and ammonium nitrate as a mobile phase. A flow injection system allows the injection of NIST 981 Pb isotopic standard, before and after the Pb peak from the sample, and the on-line addition of Tl for mass bias correction and bracketing. The procedure was validated by injecting NIST 981 into the chromatographic system and by comparing the results for real samples with the classical off-line separation procedure using Pb spec resins. The optimised procedure was applied to archaeological samples containing different concentrations of Pb. It was observed that the only limitation to the accuracy of the procedure was the concentration of Pb in the samples as no preconcentration is performed. Solid archaeological samples containing at least 500 μg g⁻¹ of Pb can be studied using the proposed procedure.

中文翻译：

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液相色谱与多接收器 ICP-MS 联用直接测定考古材料中的 Pb 同位素比率

已开发出一种通过将液相色谱与多接收器 ICP-MS 联用来测定 Pb 同位素比率的程序。该程序允许在溶解后直接注入样品，而无需求助于耗时的离线分离程序。以乙二胺四乙酸 (EDTA) 螯合物的形式使用 EDTA 和硝酸铵作为流动相，通过阴离子交换从伴生元素中分离 Pb。流动进样系统允许在来自样品的 Pb 峰之前和之后进样 NIST 981 Pb 同位素标准，以及在线添加 Tl 以进行质量偏差校正和括号。通过将 NIST 981 注入色谱系统并将实际样品的结果与使用 Pb 规格树脂的经典离线分离程序的结果进行比较，对该程序进行了验证。将优化的程序应用于含有不同浓度 Pb 的考古样品。据观察，该程序准确性的唯一限制是样品中 Pb 的浓度，因为没有进行预浓缩。含有至少 500 μg/g 的固体考古样品^-1的 Pb 可以使用建议的程序进行研究。