Simultaneous lead isotope ratio and gold-lead-bismuth concentration analysis of silver by laser ablation MC-ICP-MS

“Non-invasive” portable laser ablation sampling for lead isotope analysis of archaeological silver: a comparison with bulk and in situ laser ablation techniques

“…The methods of manufacture of the reference materials produced in house closely follow those outlined in ref. 13 and 23 some being the same materials (RMAgD-1 and RMAgS-1) and others re-homogenised by re-melting (RMAgP-2) or re-made (RMAg981-3) using the same procedure. RMAgN-2 was made from ore but was alloyed with lead to increase the lead content.…”

“…Sample availability is particularly acute for silver and other rare archaeological metals, which, because of their high cultural value and paucity, are frequently barred from invasive sampling techniques. There has been a major creative drive to develop minimally and non-invasive methods to push analytical capabilities within the eld of archaeology for more than half a century (examples for precious and copper alloys [4][5][6][7][8][9][10][11][12][13] ). The methodological advancement of mass spectrometry techniques in archaeology is not only concerned with the ability to measure smaller samples with improved accuracy and precision but also curatorial factors such as the impact to the artefact and where physical sampling takes place.…”

“…The methodological advancement of mass spectrometry techniques in archaeology is not only concerned with the ability to measure smaller samples with improved accuracy and precision but also curatorial factors such as the impact to the artefact and where physical sampling takes place. 13,14 Laser ablation (LA) is the least invasive technique developed for metal artefacts that is capable of collecting a physical sample. Laser ablation pits # 100 mm in diameter are indistinguishable from natural surface imperfections to the naked eye, and, in terms of non-invasiveness, are a substantial improvement on acid leaching and oxidation techniques, which irreversibly alter the surface of the metal, and micro drilling and abrasion with quartz, which leave visible traces, unless carefully restored by a conservator.…”

“…In situ LA-Multi-collector (MC)-ICPMS systems used for lead isotope analysis are almost exclusively equipped with nanosecond lasers. 5,13,[15][16][17] These lower frequency lasers produce a relatively heterogeneous particle size distribution and can cause a degree of inter-elemental and isotopic fractionation. [18][19][20] Combined with the low abundance of 204 Pb and isobaric interferences, this makes it difficult to measure ratios relative to 204 Pb, which leads to long-term precision of 0.3-0.4% (2 relative standard deviations).…”

“…[18][19][20] Combined with the low abundance of 204 Pb and isobaric interferences, this makes it difficult to measure ratios relative to 204 Pb, which leads to long-term precision of 0.3-0.4% (2 relative standard deviations). 5,13,16,17 Precision in this range is sufficient to answer a range of archaeological questions but is not ideal for provenance studies, for which, conventionally, precision and accuracy better than 0.1% 2RSD are desired. 3 An indirect lter sampling system using a portable LA (pLA), as successfully applied on various mediums for the measurement of lead isotope ratios (pigments, metallic lead, galena 14 ), other isotope systems (stone 21 ) and elemental concentrations (copper, 6 pigments, gold, glass 22 ), has the potential to circumvent many of the problems associated with in situ lead isotope analysis of silver by laser ablation.…”