The natural river water certified reference material SLRS‐4 (NRC‐CNRC, National Research Council‐Conseil National de Recherches Canada) has been routinely analysed for major and trace elements by six French laboratories. Most measurements were made using inductively coupled plasma‐mass spectrometry. For silicon and thirty one trace elements (rare earth elements, Ag, B, Br, Cs, Ga, Ge, Li, P, Pd, Rb, Se, Th, Ti, Tl, W, Y and Zr), no certified values are assigned by NRC‐CNRC. We propose some compilation values and related uncertainties according to the results obtained by the different laboratories.

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The plasma-derived factor VIII (pd-FVILI) circulates as different heterodimers of heavy and light chains associated by a metallic ion still present in the functional activated factor VIII trimer of molecular mass 50000-45000-70000 Da. The chelation of the metal leads to the dissociation of these complexes with a concomitant loss of the procoagulant activity. Until now, this ion has not been directly identified and its role in the structure/function relationships remains unclear. We report the first determination of the nature of this metal using atomic-absorption spectroscopy with Zeeman effect. A comparative identification was also performed with the new recombinant factor VIII, FVIII-AII. In the different active pd-FVIII heterodimers (of molecular mass ranging over 210000-80000-90000-80000 Da) and in FVIII-AII, copper was detected. This result is consistent with sequence similarities described between FVIII and copper-binding proteins. The quantification of the copper content in FVIII-A11 and in the corresponding pd-FVIII dimer of 90000-80000 Da indicated, for both proteins, the presence of one copper iordmol FVIII. Copper was also identified in the activated FVIII complex and remained in the dimer of 50000-70000 Da generated during FVIII inactivation. Further dissociation into isolated fragments of molecular masses 70000 Da and 50000 Da was concomitant with the loss of the copper ion. No copper was detected in the isolated fragment of molecular mass 45000 Da. These results suggest that the presence of the cation is not directly related to FVIII activity but is an essential structural prerequisite for FVIII heavy-lightchain association.Hemophilia A is related to the absence or to sequence modifications of factor VIII (FVIII), a glycoprotein which acts in the intrinsic coagulation pathway. The gene cloning [l] has greatly contributed to the understanding of the FVIII structure/function relationships. The amino acid sequence is predicted as a polypeptide of 2332 amino acids which exhibits a triplicated region of 330 residues (A domains), a unique region of 983 residues (B domain) and a duplicated region of 150 amino acids (C domains) arranged in the following order Al-A2-B-