A new method for stable lead isotope extraction from seawater

• We present a relatively fast (2.5–6.5 h), semi-automated system to extract Pb from seawater.
• Extraction requires few chemicals and has a relatively low blank (0.7 pmol kg−1).
• We compare analyses of Pb isotopes by HR ICP-MS with those by MC-ICP-MS.

A new technique for stable lead (Pb) isotope extraction from seawater is established using Toyopearl AF-Chelate 650 M® resin (Tosoh Bioscience LLC). This new method is advantageous because it is semi-automated and relatively fast; in addition it introduces a relatively low blank by minimizing the volume of chemicals used in the extraction. Subsequent analyses by HR ICP-MS have a good relative external precision (2σ) of 3.5‰ for 206Pb/207Pb, while analyses by MC-ICP-MS have a better relative external precision of 0.6‰. However, Pb sample concentrations limit MC-ICP-MS analyses to 206Pb, 207Pb, and 208Pb. The method was validated by processing the common Pb isotope reference material NIST SRM-981 and several GEOTRACES intercalibration samples, followed by analyses by HR ICP-MS, all of which showed good agreement with previously reported values.

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