TY - CONF A1 - Röthke, A. A1 - Richter, Silke A1 - Görlitz, V. A1 - Pape, C. A1 - Schulz, U. A1 - Jährling, R. A1 - Meinhardt, R. A1 - Koenig, M. A1 - Becker, D. A1 - Charoud-Got, J. A1 - Weber, M. A1 - Rienitz, O. T1 - As good as or even better than ID-ICP-MS? High accuracy ICP OES determination of 1 g/kg mercury solutions N2 - To establish the SI traceability of the element content w(Hg) of a gravimetrically prepared 1 g/kg mercury solution, the latter was compared to a primary reference solution by means of high accuracy inductively coupled plasma optical emission spectrometry (ICP OES) measurements. For this purpose, the ICP OES bracketing method previously described [1] was improved to yield a relative expanded uncertainty of the mercury element content of Urel(w(Hg)) = 0.5 % (with k = 2) associated with the comparison of two monoelemental solutions. In case of mercury, such a small uncertainty was achieved for the first time. Before, in general, such small uncertainties were only reported applying isotope dilution methods performed with MC-ICP-MS. However, for mercury solutions at this concentration range, several dilution steps are necessary to prepare the samples for ID-MC-ICP-MS. The sum of the uncertainty contributions stemming from the dilution steps, as well as the intrinsic difficulties of measuring mercury at low concentrations, result in an overall uncertainty of the ICP-MS measurements, which is comparable to or even larger than those, achieved with the ICP OES method applied. We will present details of the sample preparation as well as of the dedicated ICP OES measurement approach, which were crucial to achieve such a small measurement uncertainty. The newly developed method was successfully applied in the context of the development and production of elemental solution chemical reference standards (CRS), which are distributed by the EDQM. The CRS are intended to support measurements required by the European Pharmacopoeia, which has recently incorporated a new international guideline for the control of elemental impurities in medicinal products. T2 - ICP-MS Anwendertreffen CY - Berlin, Germany DA - 03.09.2018 KW - Traceability KW - Mercury solution PY - 2018 AN - OPUS4-46218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -