Example of Uncertainty Budget Estimation When Using Isotope Dilution

Example of Uncertainty Budget Estimation When Using Isotope Dilution 

A simplified bottom-up approach for estimating the measurement uncertainty of the IDMS result for an individual PGE measurement result was presented by Meisel and Moser [7]. This approach takes into account the significant uncertainty contributions. Uncertainty components related to weighing, detector dead time, gravimetric dilution, and so on, need to be considered if a complete uncertainty budget is required, but they are negligible at trace element levels. A systematic approach that takes into account correlations between the uncertainty components was presented by Moser et al. [23]. 

Uncertainties were calculated by applying the spreadsheet method developed by Kragten [24], but without taking correlations into account. The following standard uncertainties were considered, following the suggestions and rules from the Eurachem/CITAC Guide (2000) [14]. 

As the value vas close to the detection limit, 100% RSD was used as a worst-case estimate. 

As expected, depending on the concentration level, the contribution of the blank increases with decreasing concentration. 

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