Lead isotopic analysis of Antarctic snow using multi-collector ICP-mass spectrometry

• Published in: Journal of Analytical Atomic Spectrometry
• Main Authors: Bazzano, Andrea, Latruwe, Kris, Grotti, Marco, Vanhaecke, Frank
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: Chemistry; EXPONENTIAL MODEL; SHEATHING GAS; GRAM CONCENTRATIONS; ENVIRONMENTAL-SAMPLES; DOUBLE SPIKE; PB ISOTOPES; COATS LAND; MU-L MIN(-1); SAMPLE-INTRODUCTION SYSTEM; RATIO MEASUREMENTS; Antarctic; Coats Land; Antarc*
• Online Access: https://biblio.ugent.be/publication/6985571; http://hdl.handle.net/1854/LU-6985571; https://doi.org/10.1039/c4ja00484a; https://biblio.ugent.be/publication/6985571/file/6985592

Reliable determination of Pb isotope ratios in Antarctic snow is challenging because of the low analyte concentration and the low volume of sample typically available. In this work, a combination of a total sample consumption introduction system (the torch-integrated sample introduction system, TISIS) with multi-collector ICP-mass spectrometry (MC-ICP-MS) was used for this purpose. With this instrumental setup, accurate and precise determination of Pb isotope ratios was possible at concentrations as low as 0.5 ng mL(-1), while using 0.2 mL of solution only (total amount of Pb: 100 pg). At 10 ng mL(-1), the repeatability for the Pb-207/Pb-206 ratio was 0.16 parts per thousand RSD. The concentration range was further extended downwards by using 100-fold analyte element preconcentration via freeze-drying of 20 g of snow. The Pb concentration in procedural blanks was 0.5 +/- 0.3 pg g(-1), enabling the determination of Pb isotope ratios in snow samples containing down to 5 pg g(-1) of Pb. After development and validation, the procedure was applied to snow samples collected at Dome C (East Antarctic Plateau) on a monthly basis during the 2006 and 2010 campaigns. The method developed was able to reveal a seasonal variation in the Pb isotope ratios occurring during 2006 and strong inter-annual variation between the two campaigns.