CRM Tellurium (Te) - Aqueous calibration solution ASTASOL® AN90591C

Significance of the Topic

The availability of well-characterized aqueous calibration solutions is essential for ensuring the accuracy and comparability of trace element determinations in environmental, clinical and industrial laboratories. A certified reference material (CRM) for tellurium supports method validation, instrument calibration and quality control across a range of atomic and molecular spectrometric techniques.

Objectives and Study Overview

This certificate describes the preparation, certification and intended use of ASTASOL® AN90591C, an aqueous calibration solution containing tellurium at nominal concentration of 1000 mg/L. The document outlines the matrix composition, production details, metrological traceability and validation procedures securing its role as a primary calibration standard.

Methodology and Instrumentation

The solution was prepared gravimetrically from high-purity elemental tellurium (99.999%) dissolved in 20% hydrochloric acid (v/v), using sub-boil distilled acid and ultrapure water (≥18 MΩ·cm, 0.22 μm filtered). Density at 20 °C was determined to convert concentration between mass fraction and volume basis. Characterization employed:

• ICP-OES for primary concentration measurement
• Comparison against SRM NIST 3156 for independent verification
• AAS, ICP-OES and ICP-MS to quantify trace elemental impurities (all below detection limits for key elements).

Main Results and Discussion

The certified value for tellurium is 1000 ±2 mg/L (expanded uncertainty, k=2) at 20 °C, corresponding to 960 ±3 mg/kg by mass fraction. Trace impurities in the solution matrix are all below detection thresholds (<0.1 mg/L for most elements), ensuring minimal spectral interferences. Homogeneity tests confirmed uniform distribution of analyte across bottles, and stability studies guarantee integrity over the five-year shelf life under recommended storage conditions.

Benefits and Practical Applications

The CRM is intended for calibration and validation of analytical methods including AAS, AES, ICP-OES, ICP-MS, molecular absorption spectrometry and selected electroanalytical techniques. Its high purity, SI-traceability and detailed uncertainty budget make it suitable for routine QA/QC, method development and interlaboratory comparisons.

Future Trends and Applications

Advances in spectrometric instrumentation demand CRMs with lower uncertainty and broader elemental coverage. Future directions include multi-element solutions, ultra-low concentration standards for emerging contaminants and CRMs tailored for hyphenated techniques. Integration with digital certificate formats and blockchain-based traceability may further enhance reliability and data integrity.

Conclusion

ASTASOL® AN90591C provides a robust, well-characterized calibration standard for tellurium determination in acidic aqueous media. Its certified value, validated uncertainty and guaranteed homogeneity and stability support high-confidence analytical results in research and industrial laboratories.

References

• ISO Guide 31: Reference materials – Contents of certificates and labels
• ČSN EN ISO 17034:2017 – General requirements for the competence of reference material producers
• NIST SRM 3156 – Tellurium Standard Reference Material
• ČSN EN ISO/IEC 17025:2018 – General requirements for the competence of testing and calibration laboratories
• ČSN EN ISO 9001:2016 – Quality management systems