Model estimated uncertainties in the calibration of a total reflection x‐ray fluorescence spectrometer using single‐element standards

Total reflection x‐ray fluorescence (TXRF) was used for the analysis of single‐element standards, Ca, Cr, Zn, Ga, Se, Rb, Sr and Y, at various concentrations. A triplicate analysis was carried out to determine the homogeneity of the samples and the reproducibility of the results. The average estimated uncertainty (model calculated) values was compared with the predicted uncertainties (systematic or equipment related). The estimated and the predicted uncertainties showed considerable agreement except at very low concentrations resulting from excessive dilution. The discrepancies decreased as the concentrations of the analytes increased. This work indicates a very reliable dependence on the systematic or predicted uncertainties from TXRF spectrometric analysis, especially at high concentrations.