Combining method validation data with additional information for measurement uncertainty evaluation - determination...

Area of Science:

• Analytical Chemistry
• Metrology

Background:

• Measurement uncertainty evaluation combines experimental data with knowledge of uncertainty sources.
• Objective interpretation of quantification requires accounting for random and systematic effects.

Purpose of the Study:

• To assess and account for the impact of uncontrolled high temperature during sample preparation and validation data on measurement uncertainty.
• To quantify the uncertainty components in melatonin content determination in tea.

Main Methods:

• Detailed inspection of the measurand and measurement process.
• Quantification of uncertainty components using experimental data and additional information.
• Application of High-Performance Liquid Chromatography with Fluorescence Detection (HPLC-FD).

Main Results:

• Melatonin content in tea was quantified between 3.7 and 196 g kg⁻¹, with relative expanded uncertainty between 28% and 40%.
• The uncertainty was below the maximum admissible relative expanded uncertainty of 40%.
• HPLC-FD calibration instability was identified as the major uncertainty component, contributing up to 82.7%.

Conclusions:

• Experimental limitations in measurement uncertainty evaluation can be overcome through a detailed, quantitative understanding of the process.
• The study demonstrates a robust method for assessing and managing uncertainty in complex analytical measurements.
• Accurate quantification of melatonin in tea is achievable within acceptable uncertainty bounds.