Uncertainty in the multielemental quantification by total-reflection X-ray fluorescence: theoretical and empirical...

Area of Science:

• Analytical Chemistry
• Metrology
• Spectroscopy

Background:

• Quality assurance of analytical results is increasingly critical.
• Accurate uncertainty quantification is essential for reliable experimental data.

Purpose of the Study:

• To develop and compare theoretical models for expanded uncertainty in TXRF measurements.
• To identify dominant sources of uncertainty in TXRF analysis.

Main Methods:

• Proposed two theoretical models for expanded uncertainty.
• Systematically compared theoretical models with empirical TXRF data.
• Investigated potential sources of unexpected uncertainty behavior.

Main Results:

• Theoretical model B demonstrated high agreement with empirical expanded uncertainties.
• Theoretical model A partially explained instrumental repeatability.
• An unexpected U-shaped behavior in empirical uncertainty was observed.
• Sample deposition roughness and geometry were identified as major uncertainty contributors.

Conclusions:

• Theoretical model B provides a robust framework for TXRF uncertainty estimation.
• Unaccounted factors like background variations and detector nonlinearity may explain observed anomalies.
• Minimizing sample deposition variations is crucial for improving TXRF measurement accuracy.