The EDQM has updated the leaflets of its reference standards for elemental impurities (lead solution CRS, cadmium solution CRS, mercury solution CRS and arsenic solution CRS) with further information to facilitate their use and make traceability transparent. The mass fractions of the assigned element are traceable to the SI units (mole and kilogram) through an uninterrupted chain, similar to certified reference materials established by a national metrological institute.

More detailed information on the assigned value and the associated expanded uncertainty is now included in the leaflets accompanying the reference standards. In addition, the solvent composition is explicitly stated, as well as the density of the solution. The specific primary materials used to achieve the link to the SI units are also indicated.

Elemental impurities naturally occurring in the environment are amongst the greatest potential sources of contamination. Public health standards, such as the ICH Q3D Guideline for Elemental Impurities, require careful risk assessments of sources for elemental impurities. The changes are part of the EDQM’s efforts to provide efficient support to users of its pharmaceutical reference standards. These reference standards also underpin the European Pharmacopoeia (Ph. Eur.) chapter describing the determination of elemental impurities (2.4.20.).

More detail can be found in the EDQM’s “Knowledge database” by looking up General chapter 2.4.20.