CRM Ag, Hg - Aqueous calibration solution ASTASOL® AN9099MN

Significance of the Topic

A reliable aqueous calibration solution for silver (Ag) and mercury (Hg) is critical for accurate quantification in environmental, pharmaceutical, and industrial analyses. Certified reference materials (CRMs) with defined traceability and uncertainty support method validation, instrument calibration, and regulatory compliance in laboratories worldwide.

Objectives and Study Overview

The primary aim was to produce and certify ASTASOL® AN9099MN, an aqueous calibration solution containing Ag and Hg at 100 mg/L each. The study covers gravimetric preparation, verification of certified values, homogeneity, stability assessment, and documentation of trace impurities. Compliance with ISO Guide 31 and accreditation to ČSN EN ISO 17034:2017 ensures the CRM’s credibility.

Methodology and Instrumentation

Preparation involved high-purity Ag and Hg compounds dissolved in 5% sub-boiled HNO₃ and ultrapure water. Gravimetric methods provided primary value assignment with direct SI traceability. Verification employed:

• Gravimetric determination of Ag using SRM NIST 3151
• Complexometric titration of Hg with EDTA using SRM NIST 928
• Instrumental confirmation by AAS, AES, ICP-OES, and ICP-MS calibrated with independent CRMs

Used Instrumentation

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

Main Results and Discussion

The certified concentration for both Ag and Hg is 100.0 ± 0.2 mg/L (k=2) at 20 °C, corresponding to 97.4 ± 0.3 mg/kg based on a density of 1.0233 ± 0.0005 g/cm³. Trace impurity screening showed most elements below detection limits (<0.01–<0.5 mg/L), ensuring matrix cleanliness. Homogeneity tests confirmed consistency across bottles, and stability studies guarantee shelf life of three years unopened and 12 months after opening under specified conditions.

Benefits and Practical Applications

ASTASOL® AN9099MN enables precise calibration and validation of analytical methods for aqueous samples, including AAS, AES, ICP-OES, ICP-MS, molecular absorption, and selected electroanalytical techniques. Its clear specification and stability support routine quality assurance and regulatory testing.

Future Trends and Potential Applications

Developments may include multi-element CRMs covering broader analyte ranges, enhanced stability formulations for extreme conditions, miniaturized high-throughput calibration kits, and digital certification with blockchain traceability. Integration with automated sampling and real-time monitoring platforms is anticipated.

Conclusion

ASTASOL® AN9099MN is a well-characterized CRM for Ag and Hg in aqueous matrix, offering high purity, robust traceability, and low uncertainty. It meets stringent accreditation standards and supports diverse spectrometric applications in research, QA/QC, and industrial analytics.

References

• ISO Guide 31: Reference Materials – Contents of Certificates and Labels
• SRM NIST 3151: Silver Standard Reference Material
• SRM NIST 928: Mercury Standard Reference Material
• ČSN EN ISO 17034:2017 – General Requirements for the Competence of Reference Material Producers
• ČSN EN ISO/IEC 17025:2018 – General Requirements for the Competence of Testing and Calibration Laboratories
• ČSN EN ISO 9001:2016 – Quality Management Systems