Understanding Uncertainty to Weighing by Electronic-Analytical Balances

Area of Science:

• Analytical Chemistry
• Metrology
• Laboratory Measurement

Background:

• Accurate weighing using electronic-analytical balances (EABs) is crucial in analytical labs.
• Determining measurement uncertainty for EABs is controversial; manufacturer specs often don't match routine use.
• Method validation is necessary to establish true uncertainty levels.

Purpose of the Study:

• To re-evaluate Bureau International de Poids et Mesures concepts for predicting measurement uncertainty.
• To demonstrate how pooled calibrations improve the prediction of observed uncertainty.
• To simplify calculations and support scientific methodology in weighing operations.

Main Methods:

• Utilized pooled calibrations to analyze measurement uncertainty.
• Investigated the impact of including repetition uncertainty on observed uncertainty prediction.
• Assessed mass changes in certified calibration masses over time.

Main Results:

• Pooled calibrations effectively predict observed uncertainty, simplifying calculations.
• Excluding repetition uncertainty from calculations improves prediction accuracy.
• Certified calibration masses showed an average mass gain of approximately 0.001%.
• Predicted EAB uncertainty in one lab matched observed uncertainty in a geographically distinct lab.

Conclusions:

• Pooled calibrations are vital for accurately predicting the observed uncertainty of samples.
• This approach simplifies complex calculations and strengthens the scientific basis of weighing.
• Ensures reliable and consistent measurement uncertainty determination in analytical laboratories worldwide.