Uncertainty in Analytical Results from Solid Materials with Electrothermal Atomic Absorption Spectrometry. A Comparison of Methods.

The combined uncertainty in the analytical results of solid materials for two methods (ET-AAS, analysis after prior sample digestion and direct soil sampling) are derived by applying the Guide to the Expression of Uncertainty in Measurement from the International Standards Organization. For the analysis of solid materials, generally three uncertainty components must be considered: those in the calibration, those in the unknown sample measurement and those in the analytical quality control (AQC) process. For both methods, the uncertainty in the certified content of the CRM, which is used for AQC must be considered. The estimation of the uncertainty components is shown to be a suitable tool for the experimental design in order to obtain a small uncertainty in the analytical result.JRC.(EI)-Environment Institut