CRM Copper (Cu) - Aqueous calibration solution ASTASOL® AN90151N

Significance of the Topic

The accurate quantification of copper in aqueous solutions is critical for environmental monitoring, industrial process control, and quality assurance in analytical laboratories.
Certified reference materials (CRMs) like ASTASOL® AN90151N provide a benchmark for calibration and validation of spectrometric and electroanalytical methods, ensuring measurement traceability and comparability.

Objectives and Study Overview

• To produce a high-purity aqueous standard solution of copper at a certified concentration of 1000 mg/L ± 2 mg/L.
• To establish direct traceability to SI units through gravimetric preparation and validation against NIST reference materials.
• To assess homogeneity and stability over a five-year shelf life under defined storage conditions.
• To characterize trace impurities for informational purposes and support method selection.

Methodology and Production

The copper solution was prepared gravimetrically using 99.999 % pure metallic copper and diluted in 2 % sub-boiling distilled nitric acid and ultrapure water.
The density at 20 °C was determined as 1.0117 g/cm³ with an expanded uncertainty (k=2) of 0.0005 g/cm³, enabling conversion between volume- and mass-based concentrations.
Traceability was verified by complexometric titration (using NIST SRM 928) and by comparison with an independent NIST reference solution (SRM 3114).
Homogeneity was confirmed across multiple bottles, and stability studies demonstrated that the CRM remains within specification for five years when stored at 5–30 °C and at 20 ± 0.5 °C prior to use.

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)
• Complexometric titration

Key Results and Discussion

• The certified copper concentration is 1000 ± 2 mg/L, with mass fraction 988 ± 3 mg/kg derived from density measurements.
• Trace elements were quantified by AAS, ICP-OES, and ICP-MS, all remaining below parts-per-million levels and thus not affecting calibration performance.
• The CRM exhibited consistent homogeneity and maintained its integrity under recommended storage, with no significant drift observed.

Benefits and Practical Applications

• Provides a reliable calibration standard for AAS, AES, ICP-OES, ICP-MS, molecular absorption spectrometry, and select electroanalytical techniques.
• Ensures SI-traceable results and supports quality control in environmental, pharmaceutical, and industrial laboratories.
• Enhances method validation, inter-laboratory comparability, and regulatory compliance.

Future Trends and Applications

As analytical demands evolve, CRMs like ASTASOL® AN90151N will expand to cover ultratrace levels, multi-element matrices, and compliance with emerging digital certification systems.
Integration with laboratory information management systems (LIMS) and digital certificates will streamline method validation and data integrity in high-throughput environments.

Conclusion

ASTASOL® AN90151N represents a rigorously certified and homogenous copper calibration solution with direct SI traceability, making it an indispensable tool for accurate and reliable analytical measurements across various techniques and industries.

References

• ISO Guide 31: Reference Materials – Contents of Certificates and Labels.
• NIST SRM 928: Complexometric Titration Standard.
• NIST SRM 3114: Copper in Aqueous Solution Standard.