Chernonozhkin, Stepan M.

Degryse, Patrick

Van Acker, Thibaut

Van Ham-Meert, Alicia

Van Malderen, Stijn

Vanhaecke, Frank

English

Ghent University Academic Bibliography

Assessment of ns-LA-MC-ICP-MS for Pb and Sr isotopic analysis of archaeological glass – mass bias correction strategies and Corning glass standards Alicia Van Ham-Meert1, Stepan Chernonozhkin2, Stijn J. M. Van Malderen2, Thibaut Van Acker2, Frank Vanhaecke2, Patrick Degryse1 1Earth and Environmental Science, Archaeological Science, KU Leuven, Celestijnenlaan 200E, 3001 Heverlee (Belgium) 2 Department of Analytical Chemistry, Ghent University, Campus Sterre, Krijgslaan 281-S12, 9000 Ghent, Belgium Isotopic analysis of lead (Pb) and strontium (Sr) is of particular importance to  archaeometry (Stos-Gale,1992; Aggarwal et al. 2008). Lead isotopic signatures of metallic objects are commonly used for provenancing purposes, i.e. to determine the geologic origin of the Pb-bearing ore and possibly the associated manufacturer workshop locations. Lead was also used as a flux in lead-glasses and  glazes, or as an opacifying agent in glass. Low levels of Pb in glass can originate from the heavy mineral fraction of sand, the source material of the network former. The study of Pb isotope ratios in glass has proven useful in either determining the sand source, or the source of the Pb added to the glass (Degryse, 2013). The 87Sr/86Sr isotope ratio is measured to determine the source of lime in glass, though the Sr might also come from some minerals in the silica source. Quantification of Sr can help discriminating between those two cases (Degryse, 2013). When analysing archaeological objects, (quasi-) non-destructive techniques are preferable. The damage inflicted on the sample surface by laser ablation sampling is substantially smaller in scale than that caused by micro-coring followed by digestion, hence the former is preferred for the present study. Furthermore, sampling by laser ablation allows spatially resolved isotopic data to be obtained for samples with multiple glass types. Finally, it improves throughput by circumventing time-consuming digestion procedures.  Two main challenges need to be addressed in this approach: (i) instrumental- and laser-induced mass bias, which needs to be adequately corrected for, and (ii) the necessary availablity of matrix-matched standards of glass with accurately and precisely known isotopic compositions. Matrix matching is especially important when sampling relies on lasers with nanosecond pulse duration, as they produce more melting and larger condensed particles (than lasers with femtosecond pulse duration), inducing elemental fractionation.  This paper will compare different mass bias correction strategies: a. internal correction using either the response for a pair of isotopes of the target element or for a pair of isotopes of a nebulized internal standard, whilst relying on the exponential or power law correction methods b. external correction using a sample standard bracketing approach c. combination of both internal and external correction  High-precision Pb and Sr isotope ratio measurements of Corning glasses A, B, C, and D (Corning Museum of Glass, United States, New York) were also performed. These glasses, which are widely used in EPMA or XRF analysis, were specifically synthesized to mimick the matrix of ancient glasses and, hence, are appropriate candidates to serve as matrix-matched reference materials in an archaeological context.   References Aggarwal, J., Habicht-Mauche, J., Juarez, C., (2008) Application of heavy stable isotopes in forensic isotope geochemistry: A review. Applied Geochemistry, 23, 2658-2666. Degryse, P., (2013) Isotope-Ratio Techniques in Glass Studies, in: Janssens, K. (es.): Modern Methods for Analysing Archaeological and Historical glass. Wiley, Vol.1, p.235-245 Stos-Gale, Z.A., (1992) Isotope archaeology: reading the past in metals, minerals, and bone. Endeavour, 16, 85- 90. 

Assessment of ns-LA-MC-ICP-MS for Pb and Sr isotopic analysis of archaeological glass : mass bias correction strategies and Corning glass standards

https://biblio.ugent.be/publication/8107781/file/8107957

Assessment of ns-LA-MC-ICP-MS for Pb and Sr isotopic analysis of archaeological glass : mass bias correction strategies and Corning glass standards

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