2004 Denver Annual Meeting (November 7–10, 2004)

Paper No. 10
Presentation Time: 10:30 AM

AN ADAPTED COLUMN CHEMISTRY PROCEDURE FOR SEPARATION OF FE, CU AND ZN FROM GEOLOGICAL MATRICES, AND NATURAL ZN ISOTOPIC VARIATIONS IN GEOLOGICAL STANDARD REFERENCE MATERIALS BCR-027, BCR-030 AND NOD-P-1


CHAPMAN, John B.1, MASON, Thomas F.D.2, WEISS, Dominik J.2, COLES, Barry J.2 and WILKINSON, Jamie J.2, (1)Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, United Kingdom, (2)Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, john.chapman@imperial.ac.uk

The aims of this study were to refine previously published column chemistry procedures to achieve optimum elution-profile and recovery when analysing geological materials, and to measure natural Zn, Cu and Fe isotope variations in a range of geological standard reference materials (SRM). High analyte ratios (e.g. Fe/Cu) are a problem when analysing geological materials, especially ore minerals. High element concentrations – particularly P and Fe – relative to trace analytes cause premature elution, resulting in reduced recovery and contamination of other element fractions. Our improved chromatography gives high-yield (>99%) elemental separates for Fe, Cu and Zn, free from significant major and minor elements. Analyte purity has been verified by ICP-AES, isobaric interferences by three-isotope plots on Fe and Zn, and non-spectral interferences by ICP-MS sensitivity comparison. Data quality has been assessed using industrial single-element solutions, geological SRM, in-house and international isotopic standards, and inter-laboratory comparison. Isotope analysis for SRM samples BCR-027 (blende ore), BCR-030 (calamine ore), and NOD-P-1 (ferromanganese nodule) has yielded ä66Zn values (relative to in-house standard IMP ZnTM) of 0.248 ±0.07‰ (2s), -0.147 ±0.115‰ (2s), and 0.933 ±0.05‰ (2s) respectively. Long-term reproducibility, using industrial standard Romil Zn, is good (±0.045‰ per amu, n=7, over two years). I aim also to present further Zn, Fe and Cu data for SRM samples BCR-027, NOD-P-1, BCR-1 and SU-1, as well as preliminary results for isotopic studies of the Cumbrian hematite deposits.