This report describes the production of ERM-BB185, which is a bovine liver material certified for the mass fraction of As, Cd, Cu, Mn, Pb, Se and Zn. This material was produced following ISO Guide 34:2009 and is certified in accordance with ISO Guide 35:2006. This CRM is produced and certified to replace the CRM BCR-185R.
The CRM was produced from raw livers from cattle slaughtered in Belgium. The raw livers were cut into cubes and freeze dried. The freeze dried cubes were milled and sieved to obtain a fine powder. The powder was homogenised and afterwards checked for water content and particle size distribution. The homogenised powder was put in vials and packed in aluminised pouches.
Between unit-homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006.
The material was characterised by an interlaboratory comparison of laboratories of demonstrated competence and adhering to ISO/IEC 17025. Technically invalid results were removed but no outlier was eliminated on statistical grounds only.
Uncertainties of the certified values were calculated in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity, instability and characterisation.
The material is intended for the quality control and assessment of method performance. As with any reference material, it can be used for establishing control charts or validation studies. The CRM is available in amber glass vials containing at least 10 g of dried powder which were sealed under an atmosphere of argon and packed in aluminised pouches. The minimum amount of sample to be used is 400 mg.