The certificate for the IAEA-456 CRM is the only official source for the trace elements mass fractions certified values and their expanded uncertainties.
| Analyte | Unit | Certified value⁽ᵃ⁾ | Expanded uncertainty⁽ᵇ⁾ |
| Al | g kg-1 | 55.4 | 4.0 |
| As | mg kg-1 | 6.14 | 0.52 |
| Cd | mg kg-1 | 0.198 | 0.02 |
| Co | mg kg-1 | 4.72 | 2.5 |
| Cr | mg kg-1 | 589 | 42 |
| Cu | mg kg-1 | 44.6 | 2.4 |
| Fe | g kg-1 | 49.5 | 3.2 |
| Hg | mg kg-1 | 0.077 | 0.005 |
| CH3Hg | µg kg-1 as Hg | 0.125 | 0.019 |
| Mn | mg kg-1 | 825 | 52 |
| Ni | mg kg-1 | 760 | 56 |
| Pb | mg kg-1 | 33.4 | 2.1 |
| V | mg kg-1 | 223 | 16 |
| Zn | mg kg-1 | 203 | 9 |
(a) Information on calculation of certified values
Certified values are calculated from the accepted data sets, each set being obtained by a different laboratory and/or a different method of determination following ISO Guide 35 ‘Reference materials – General and statistical principles for certification’.
(b) Information on method used for uncertainty estimation
The uncertainty is expressed as a combined uncertainty with a coverage factor k = 2, corresponding to a level of probability 95%, estimated in accordance with the JCGM 100:2008 ‘Evaluation of measurement data – Guide to the expression of uncertainty in measurement’ and ISO Guide 35.
The assigned property values were established, considering the results reported by expert laboratories, participating in the characterisation campaign for the IAEA-456. The characterisation campaign was organised by the IAEA Environment Laboratories in Monaco. The details concerning the production process and all reported results, as well as the criteria for the assignment of property values are presented in the certification report for the IAEA-456.
