CRM Phosphates (PO43-) - Aqueous calibration solution ASTASOL® ANS077

Significance of the Topic

This certified reference material (CRM) for phosphate calibration addresses a critical need for accurate and traceable measurements in environmental monitoring, industrial quality control, and water analysis. Phosphate determination is essential for assessing water quality, nutrient management, and process control across various industries.

Objectives and Overview

The certificate describes the production, characterization, and intended use of the ASTASOL® ANS077 aqueous calibration solution containing phosphate at 1 000 mg/L. The main goal is to provide users with a stable, homogeneous, and SI-traceable standard for method calibration and validation in techniques such as spectrometry and chromatography.

Methodology and Characterization

The primary preparation method is gravimetric dissolution of highly pure ammonium dihydrogen phosphate (NH4H2PO4, 99.999%) in ultrapure water. This approach ensures direct traceability to the kilogram SI unit. The assigned concentration and its expanded uncertainty (k=2) were confirmed by:

• Gravimetric analysis
• Ionic chromatography using CRM AN90771H as calibrant

Trace impurities were limited to a maximum of 0.5 mg/L total, and homogeneity and stability tests support the material’s shelf life and performance under specified conditions.

Použitá instrumentace

• Atomic Absorption Spectrometry (AAS)
• Atomic Emission Spectrometry (AES)
• Ionic Chromatography (IC)
• Molecular Absorption Spectrometry
• Selected Electroanalytical Methods

Main Results and Discussion

The CRM was certified at a phosphate concentration of 1 000 mg/L with an expanded uncertainty of ±5 mg/L at 20 °C. Batch No. 1040 was produced on 20 January 2023, with a shelf life of three years prior to opening and an expiry of 12 months after first opening under recommended storage conditions (5–30 °C). The material’s stability and homogeneity have been demonstrated throughout this period.

Benefits and Practical Applications

• Reliable calibration for environmental and industrial water testing
• Traceable measurements supporting regulatory compliance
• Versatility across spectroscopic and chromatographic techniques
• Improved confidence in analytical results due to low uncertainty and proven stability

Future Trends and Possible Uses

Advances in on-site and portable analysis create demand for stable, transportable standards. Development of multi-element and matrix-matched CRMs may enhance method validation for complex samples. Integration with digital calibration and automated workflows will further streamline laboratory operations and data integrity.

Conclusion

The ASTASOL® ANS077 phosphate CRM offers a well-characterized, SI-traceable standard suitable for a range of analytical methods. Its high purity, controlled uncertainty, and proven stability make it an indispensable tool for precise phosphate quantification in water and related matrices.

References

Analytika, spol. s r.o. Certificate for ASTASOL® ANS077 Aqueous Calibration Solution, Version 01, 20 January 2023.