Uncertainty due to volumetric operations is often underestimated

Area of Science:

• Analytical Chemistry
• Metrology

Background:

• Accurate uncertainty estimation is crucial for reliable analytical measurements.
• Current methods may underestimate uncertainty associated with volumetric operations in titration.

Purpose of the Study:

• To evaluate minimum and maximum combined standard uncertainties for titration standards.
• To compare calculated uncertainties with reproducibility standard deviations.
• To identify and rank contributions to titrimetric uncertainty.

Main Methods:

• Evaluation of fifteen international titration standards.
• Determination of minimum and maximum combined standard uncertainties under varying analytical conditions (thorough vs. high time pressure).
• Calculation of realistic standard uncertainties for individual influence quantities using a top-down approach.

Main Results:

• Combined standard uncertainties were determined, with maximum values reflecting high time pressure.
• A top-down approach revealed volumetric operation uncertainties up to four times higher than bottom-up estimates.
• A ranking of uncertainty contributions for titrimetric results was established.

Conclusions:

• Uncertainty in volumetric operations during titration is likely significantly underestimated.
• The top-down approach provides a more realistic assessment of titration uncertainty.
• Understanding uncertainty contributions is vital for improving analytical method accuracy.