The IRMM--International Measurement Evaluation Program (IMEP). IMEP-3--trace elements in synthetic and natural water

Area of Science:

• Analytical Chemistry
• Environmental Science

Background:

• International Measurement Evaluation Program (IMEP) aims to establish measurement comparability for field laboratories.
• Traceability to the SI Unit for amount of substance (mole) is crucial for reliable chemical measurements.

Purpose of the Study:

• To evaluate international measurement comparability for trace element determination in water samples.
• To assess the performance of laboratories using routine methods against certified values.

Main Methods:

• Determination of 10 trace elements (B, Ca, Cd, Cu, Fe, K, Li, Pb, Rb, Zn) in synthetic and natural water.
• Comparison of participant results with certified values obtained via Isotope Dilution Mass Spectrometry and Neutron Activation Analysis.
• Utilizing Youden graphs for performance evaluation of 64 participating laboratories.

Main Results:

• A significant spread of results, exceeding 50% asymmetrically around the certified values, was observed.
• The study identified variability in the performance of laboratories in trace element analysis.
• Youden graphs provided a clear graphical representation of laboratory performance.

Conclusions:

• The IMEP-3 round demonstrated challenges in achieving international measurement comparability for trace elements in water.
• Routine laboratory methods showed considerable variation, impacting the reliability of results.
• Further efforts are needed to improve measurement consistency and traceability in environmental analysis.