CRM Ag, Hg - Aqueous calibration solution ASTASOL® AN9099MN

Importance of the topic

The accurate calibration of analytical instruments for silver (Ag) and mercury (Hg) determination is essential in environmental monitoring, quality control, and research laboratories. Certified aqueous calibration solutions like ASTASOL® AN9099MN provide traceable, homogeneous standards that ensure consistency and reliability in quantitative measurements.

Objectives and overview

This document certifies ASTASOL® AN9099MN as a reference material for Ag and Hg at mass fractions of 100.0 mg/L each. It outlines the preparation, certification, and intended use of the solution, ensuring direct traceability to SI units and compliance with ISO Guide 31 and ISO 17034 requirements.

Methodology and preparation

The solution is gravimetrically prepared by dissolving high-purity primary compounds (Ag 99.9999 %, Hg 99.999 %) in 5 % (v/v) sub-boiling distilled HNO₃ and ultrapure water. Density (1.0233 g/cm³, expanded uncertainty ±0.0005 g/cm³, k=2) and mass fraction were derived from this preparation. Homogeneity and stability studies confirm uniform distribution and shelf life under specified storage conditions.

Instrumentation

• Gravimetric balance for bulk preparation and concentration assignment
• Complexometric titration with EDTA for Hg determination, traceable to SRM NIST 928
• AAS, AES, ICP-OES for primary verification and impurity screening
• ICP-MS for low-level impurity detection

Main results and discussion

The certified concentrations are 100.0 ± 0.2 mg/L (100.0 ± 0.3 mg/kg) for both Ag and Hg at 20 °C. Trace impurities across the periodic table are below detection limits, with most elements measured at <0.05 mg/L. The solution’s homogeneity and stability remain intact for three years unopened, and twelve months after initial opening if stored between 5–30 °C.

Benefits and practical applications

ASTASOL® AN9099MN serves as a reliable calibrant for atomic spectrometric methods (AAS, AES, ICP-OES, ICP-MS), molecular absorption spectrometry, and selected electroanalytical techniques. Its direct SI traceability and verified uncertainty support method validation, instrument calibration, and quality assurance in industrial, environmental, and research settings.

Future trends and potential uses

Ongoing advances in spectrometry, such as high-resolution ICP-MS and laser-based techniques, will benefit from certified solutions with lower uncertainty and expanded analyte scopes. Custom multi-element aqueous CRMs and digital certification data may streamline automated calibration and enhance instrument interoperability.

Conclusion

ASTASOL® AN9099MN offers a rigorously certified, stable, and homogeneous calibration standard for Ag and Hg analysis. Its traceability, low uncertainty, and broad applicability make it a valuable resource for laboratories demanding high-quality quantitative measurements.

References

• SRM NIST 3151: Silver Standard Reference Material
• SRM NIST 928: Mercury (II) Standard Reference Material