CRM Ca, K, Mg, Na - Aqueous calibration solution ASTASOL® AN9091MN

Significance of the Topic

Aqueous calibration solutions are fundamental in quantitative elemental analysis across industries such as environmental monitoring, food safety, pharmaceuticals and materials testing. Certified reference materials (CRMs) like ASTASOL® AN9091MN ensure traceability to SI units, reduce measurement uncertainty and provide confidence in method validation and instrument calibration.

Objectives and Overview of the Certificate

The primary objective of this certificate is to document the preparation, characterization and intended use of ASTASOL® AN9091MN, an aqueous multi-element CRM containing calcium, potassium, magnesium and sodium at nominal concentrations of 1 000 mg/L. The certificate aligns with ISO Guide 31 and ISO 17034 requirements, providing production details, homogeneity, stability and traceability information.

Applied Methodology and Instrumentation

The CRM was produced gravimetrically using high-purity primary compounds (CaCO₃, KNO₃, Mg metal, NaNO₃) and acidified with sub-boiled HNO₃ to 2 % (v/v). Verification of certified values and uncertainties employed:

• Complexometric titration with EDTA for Ca and Mg, referenced to NIST SRM 928 and SRM 3109a (Ca) and SRM 928 and SRM 3131a (Mg).
• ICP-OES for K and Na, calibrated against in-house standards and NIST SRM 3152a (Na).
• AAS, ICP-OES and ICP-MS for determination of trace impurities.

The solution density (1.0213 ± 0.0005 g/cm³ at 20 °C) was measured gravimetrically and used to derive mass fractions.

Main Results and Discussion

Each analyte concentration is certified at 1 000 ± 2 mg/L (expanded uncertainty k = 2). Mass fractions are 979 ± 3 mg/kg, calculated from density. Trace impurities for over 60 elements were quantified or reported as below detection limits, confirming high purity. Homogeneity studies demonstrated negligible between-bottle variability, and stability tests guarantee shelf life of five years under 5–30 °C. Expiry after first opening is 12 months.

Benefits and Practical Applications

ASTASOL® AN9091MN is ideal for:

• Calibration of atomic spectrometric techniques (AAS, AES, ICP-OES, ICP-MS).
• Validation of molecular absorption and selected electroanalytical methods.
• Quality control in regulated laboratories requiring traceable standards.

The CRM’s rigorous characterization and uncertainty budget support accurate quantification and interlaboratory comparability.

Future Trends and Opportunities

Emerging needs in ultra-trace analysis and multi-element speciation may drive development of CRMs with lower uncertainty, extended analyte panels and matrix matching to complex sample types. Integration with digital calibration certificates and QR-coded traceability data could further streamline lab workflows.

Conclusion

ASTASOL® AN9091MN represents a high-quality, SI-traceable aqueous calibration solution for four major cations. Its certified values, comprehensive impurity profile, proven homogeneity and stability make it a reliable tool for method development, validation and routine calibration in modern analytical laboratories.

References

1. NIST SRM 928: Multi-element standard for complexometric titration.
2. NIST SRM 3109a: Calcium standard.
3. NIST SRM 3131a: Magnesium standard.
4. NIST SRM 3152a: Sodium standard.