CRM Sodium (Na) - Aqueous calibration solution ASTASOL® AN903510N

Importance of the Topic

Aqueous calibration standards with well‐defined composition and traceability are fundamental tools in analytical chemistry. They ensure accuracy and comparability of quantitative results across laboratories and methods, supporting routine quality control and high‐precision research applications.

Objectives and Overview

This certificate describes the production, characterization, homogeneity, and stability of ASTASOL® AN903510N, a certified reference material (CRM) for sodium quantification. The document aims to provide users with all necessary information for proper use in calibration and validation of atomic and molecular spectrometric methods.

Methodology and Instrumentation

Production and Certification Process:

• Gravimetric preparation using high‐purity Na₂CO₃ (99.999 %) dissolved in 2 % HNO₃.
• Generation of direct traceability to the SI unit kilogram.

Characterization and Verification:

• ICP-OES and independent comparison with NIST SRM 3152a for sodium concentration and uncertainty assessment.
• Trace impurity analysis by AAS, ICP-OES, and ICP-MS to document potential interferents (levels reported below detection limits for most elements).

Instrumentation Used:

• Atomic Absorption Spectrometry (AAS)
• Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES)
• Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

Main Results and Discussion

Certified Value:

• Concentration of sodium: 10 000 ± 20 mg/L at 20 °C
• Mass fraction: 9 661 ± 30 mg/kg (derived from density)
• Density: 1.0351 ± 0.0005 g/cm³ at 20 °C

Trace Impurities:
All analyzed elements were found below specified detection limits, confirming the high purity of the CRM. Homogeneity and Stability:
The material demonstrated uniform distribution of sodium and stable performance over the 5-year shelf life when stored between 5 – 30 °C and used under recommended conditions.

Benefits and Practical Applications

• Reliable calibration for atomic spectrometric techniques (AAS, AES, ICP-OES, ICP-MS).
• Validation of molecular absorption and selected electroanalytical methods.
• Enhanced interlaboratory comparability and method validation in QA/QC environments.

Future Trends and Applications

Development of multi‐element aqueous CRMs with lower uncertainty and extended stability at varying temperatures. Expansion of trace impurity profiling to support ultratrace analysis in emerging fields such as environmental monitoring and food safety.

Conclusion

ASTASOL® AN903510N offers a rigorously characterized sodium standard with direct SI traceability, low uncertainty, and robust stability. It supports a wide range of analytical techniques, contributing to consistent and accurate quantitative measurements in laboratories worldwide.

References

• ISO Guide 31: Reference Materials – Contents of Certificates and Labels.
• ČSN EN ISO 17034:2017 – General Requirements for the Competence of Reference Material Producers.
• NIST SRM 3152a – Sodium Standard Reference Material.