CRM Ammonium (NH4+) - Aqueous calibration solution ASTASOL® AN90801H

Importance of the topic

Calibration solutions for ammonium analysis are essential to guarantee accuracy, traceability, and comparability of results in environmental monitoring, water quality control, industrial process management, and research laboratories. Certified reference materials (CRMs) like ASTASOL® AN90801H underpin method validation, quality assurance, and regulatory compliance across various analytical techniques.

Aims and overview

ASTASOL® AN90801H is an aqueous certified reference material developed to provide a precisely defined ammonium (NH4+) concentration of 1000 mg/L. This certificate details its composition, uncertainty, traceability, storage instructions, and intended applications, ensuring consistent calibration and validation of analytical methods.

Methodology and instrumentation

• Gravimetric preparation: High-purity NH4Cl (99.999 %) was weighed to achieve a nominal concentration with direct SI traceability.
• Alkalimetric titration: Confirmed certified value (1000 mg/L) and determined expanded uncertainty (±2 mg/L, k=2).
• Ion chromatography: Screened for common anionic impurities (Br–, Cl–, F–, I–, NO2–, NO3–, PO43–, SO42–), all found below the detection limits.

Key results and discussion

• Certified concentration: 1000 mg/L ±2 mg/L (k=2) at 20 °C; mass fraction: 1000 mg/kg ±3 mg/kg.
• Solution density: 0.9997 g/cm³ ±0.0005 g/cm³ at 20 °C.
• Trace impurities: All anions below detection limits (<0.02–0.05 mg/L), ensuring negligible matrix effects.
• Homogeneity and stability: Demonstrated uniformity and guaranteed stability throughout the three-year shelf life under proper storage conditions.

Benefits and practical applications

ASTASOL® AN90801H supports accurate calibration and validation of diverse analytical methods, including:

• Atomic spectrometry (AAS, AES, ICP-OES, ICP-MS)
• Molecular absorption spectrophotometry
• Selective electroanalytical techniques

Its defined uncertainty, SI-traceability, and low impurity profile facilitate robust QA/QC protocols in environmental, industrial, and research laboratories.

Future trends and potential applications

• Extension of CRM portfolios to cover additional concentration ranges and multi-analyte mixtures.
• Integration with digital laboratory information management systems for automated calibration tracking.
• Development of temperature-robust formulations to broaden storage and usage conditions.
• Enhanced sustainable packaging and waste-reduction strategies for long-term storage.

Conclusion

ASTASOL® AN90801H is a high-purity, SI-traceable CRM for ammonium in aqueous matrices, offering low uncertainty and minimal impurities. It is a critical tool for ensuring analytical accuracy and comparability across spectrometric and electroanalytical methods.

Reference

• ASTASOL® AN90801H Certificate, Analytika, spol. s r.o., August 2023