TY - CONF A1 - Brauckmann, C. A1 - Pramann, A. A1 - Rienitz, O. A1 - Schulze, A. A1 - Phukphatthanachai, P. A1 - Vogl, Jochen T1 - Combining Isotope Dilution and Standard Addition - Elemental Analysis in Complex Samples N2 - A new method combining isotope dilution mass spectrometry (IDMS) and standard addition has been developed to determine the mass fractions w of different elements in complex matrices: (a) silicon in aqueous tetramethylammonium hydroxide (TMAH), (b) sulfur in biodiesel fuel, and (c) iron bound to transferrin in human serum. All measurements were carried out using inductively coupled plasma mass spectrometry (ICP–MS). The method requires the gravimetric preparation of several blends (bi)—each consisting of roughly the same masses (mx,i) of the sample solution (x) and my,i of a spike solution (y) plus different masses (mz,i) of a reference solution (z). Only these masses and the isotope ratios (Rb,i) in the blends and reference and spike solutions have to be measured. The derivation of the underlying equations based on linear regression is presented and compared to a related concept reported by Pagliano and Meija. The uncertainties achievable, e.g., in the case of the Si blank in extremely pure TMAH of urel (w(Si)) = 90% (linear regression method, this work) and urel (w(Si)) = 150% (the method reported by Pagliano and Meija) seem to suggest better applicability of the new method in practical use due to the higher robustness of regression analysis. T2 - CITAC Best Paper Award Ceremony CY - Online meeting DA - 21.06.2022 KW - Isotope dilution mass spectrometry KW - Standard addition KW - ICP-MS KW - Blank characterization KW - Silicon KW - Sulfur KW - Transferrin KW - Tetramethylammonium hydroxide KW - Biodiesel fuel KW - Human serum PY - 2022 AN - OPUS4-55032 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pramann, A. A1 - Vogl, Jochen A1 - Flierl, L. A1 - Rienitz, O. T1 - Determination of absolute (SI‐traceable) isotope ratios: The use of Gravimetric Isotope Mixtures N2 - The presentation is brief overview on how to use gravimetric isotope mixtures to determine SI traceable isotope ratios. There is no mass spectrometer on earth that directly measures isotope ratios. Mass spectrometers will always measure signal intensity ratios instead. The actual problem is that the measured intensity ratios differ more or less from the isotope ratios. The difference can be up to more than 10 % in case of lithium while it‘s below 1 % in case of the heavier elements like lead or uranium. Consequently, the signal intensity ratios are expressed for example in V/V depending on the type of mass spectrometer you are using, while the isotope ratios are expressed in mol/mol. This phenomenon is called Instrumental Isotopic Fractionation (or short IIF) but the more common name is still mass bias (even though this name is not entirely correct). To convert the measured into the isotope ratio usually a simple multiplication with a so-called correction (or short K) factor is done. Therefore, the problem is to determine the K factor. In absence of isotope reference materials the golden route is via gravimetric isotope mixtures, which will be explained within the presentation. T2 - CCRI-CCQM Workshop on the use of mass spectrometry in radionuclide metrology: Opportunities and challenges - Video Tutorial CY - Online meeting DA - 14.02.2023 KW - Absolute isotope ratio KW - Traceability KW - Uncertainty KW - Isotope mixtures PY - 2023 AN - OPUS4-57172 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rienitz, O. T1 - Isotope analysis for environmental and climate studies T2 - EMRP Workshop at the TC-MC Meeting of EURAMET CY - Braunschweig, Germany DA - 2013-02-07 PY - 2013 AN - OPUS4-27892 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -