CRM Silver (Ag) - Aqueous calibration solution ASTASOL® AN90011N

Significance of the Topic

Aqueous calibration solutions certified as reference materials play a critical role in ensuring accuracy, comparability and traceability of quantitative analytical results in fields ranging from environmental monitoring to pharmaceutical quality control. High-purity silver calibration solutions such as ASTASOL® AN90011N are specifically valued for the validation and calibration of atomic spectrometric and electroanalytical techniques, where precise silver quantification is required.

Objectives and Study Overview

This certificate describes the preparation, certification and recommended handling of ASTASOL® AN90011N, an aqueous silver reference material. The primary objectives are:

• To provide a fully traceable silver standard at 1 000 mg/L concentration with known uncertainty.
• To document matrix composition, homogeneity, stability and trace impurity profile.
• To define storage, handling and expiration criteria ensuring reliability across its shelf life.

Methodology and Used Instrumentation

The calibration solution was prepared gravimetrically from 99.9999 % pure silver metal and diluted in 2 % nitric acid. Key aspects include:

• Gravimetric preparation ensuring direct traceability to the SI kilogram.
• Verification of certified concentration by gravimetric determination of AgCl and comparison with SRM NIST 3151.
• Impurity screening conducted by atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS).

Key Results and Discussion

The certified silver concentration is 1 000 ± 2 mg/L at 20 °C, equivalent to 985 ± 3 mg/kg mass fraction. Density was determined as 1.0150 ± 0.0005 g/cm³. Trace impurities are reported below detection limits for most elements, confirming high purity suitable for calibration. Homogeneity tests demonstrated uniform distribution of silver across bottles, and stability studies confirmed unchanged concentration over the three-year shelf life when stored at 5–30 °C.

Benefits and Practical Applications

This reference material supports the calibration and quality control of analytical methods including:

• Flame and graphite furnace AAS
• ICP-OES and ICP-MS
• Molecular absorption spectrometry
• Electroanalytical techniques

Its high purity, well-characterized uncertainty and SI traceability improve inter-laboratory comparability and regulatory compliance in QA/QC laboratories.

Future Trends and Potential Applications

Advances in ultra-trace analysis and miniaturized instrumentation will demand even lower uncertainty standards and broader matrices. Future developments may include multi-element calibration solutions, isotope-labeled standards, and on-demand generation of calibration fluids. Integration into automated calibration systems and digital certificates with embedded data will further streamline laboratory workflows.

Conclusion

ASTASOL® AN90011N provides a high-purity, SI-traceable silver calibration solution with well-documented uncertainty, stability and homogeneity. Its rigorous certification and detailed handling instructions ensure reliable calibration across a variety of spectrometric and electroanalytical methods, supporting accurate and comparable analytical results.

Reference

ISO Guide 31:2015 – Reference Materials – Contents of Certificates and Labels