Direct Determination of Lead Isotope Ratios by Laser Ablation-Inductively Coupled Plasma-Quadrupole Mass Spectrometry in Lake Sediment Samples |
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| Authors: | Sébastien Aries Mikael Motelica-Heino Rémi Freydier Thierry Grezes Mireille Polvé |
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| Institution: | Laboratoire de Mécanismes de Transfert en Géologie, 38, rue des trente six ponts, 31400 Toulouse, France Institute of Environmental and Natural Sciences, Lancaster University, Lancaster LA1 3PP, UK |
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| Abstract: | A direct method for the determination of lead isotopic ratios by laser ablation-inductively coupled plasma-quadrupole mass spectrometry (LA-ICP-QMS) is presented. Samples of lake sediments were ground and pressed as pellets before being analysed. Mass bias was corrected by analysing an external calibration sample manufactured with pure silica doped with NIST SRM 981 solution. The efficiency of the mass bias correction was checked by comparing the ICP-MS data with lead isotopic ratios determined by thermal ionisation mass spectrometry (TIMS). The average long term reproducibilities were 0.40%, 0.40%, 0.20% and 0.30% (RSD) respectively for the 206Pb/204Pb, 207Pb/204Pb, 206Pb/207Pb and 208Pb/206Pb ratios. The method was applied to the study of lake sediment samples, in order to determine the amount and origin of historical contamination by lead. |
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| Keywords: | ablation laser spectrométrie de masse -torche à plasma induit rapports isotopiques du plomb sédiments lacustres |
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