Matrix CRM of sewage sludge METRANAL® CRM AN-OK03 - Adsorbable organically bound halogens (AOX)

Significance of the Topic

Quality control for trace halogen analysis in environmental matrices is essential for monitoring organic pollutants and ensuring compliance with regulatory standards. Certified reference materials provide the backbone for method accuracy and interlaboratory comparability.

Goals and Study Overview

This certificate describes the characterization of a sewage sludge matrix CRM (METRANAL® CRM AN-OK03) for Adsorbable Organically Bound Halogens (AOX). The aim is to establish a reliable reference value to support metrological traceability, method validation, and value transfer between laboratories.

Methodology and Instrumentation

The material consists of gamma-stabilized sludge powder (<100 µm) packaged in amber glass. The certified AOX value (280 ± 13 mg/kg dry mass, k=2) was obtained via interlaboratory comparison among accredited labs. Recommended analytical approaches include microcoulometry with argentometric titration or equivalent techniques. Sample preparation follows EPA 1650, DIN 38414-18 or similar protocols, with dry mass correction at 105 °C.

Main Results and Discussion

Homogeneity and short-term stability were confirmed according to ISO Guide 35 requirements. Metrological traceability is achieved through calibration with certified standards and co-analysis of similar matrix CRMs. The product’s shelf life is five years from April 2020, under storage at 2–10 °C.

Benefits and Practical Applications

• Ensures consistent AOX measurement and comparability across laboratories
• Supports validation and quality assurance of analytical methods
• Facilitates environmental monitoring and wastewater treatment evaluation

Future Trends and Potential Applications

Advances may include integration with automated coulometric systems, development of portable sensors for on-site AOX screening, and expansion of CRM portfolios to emerging halogenated contaminants. Digital certification and blockchain-based traceability can further enhance material provenance.

Conclusion

METRANAL® CRM AN-OK03 represents a robust and well-characterized tool for AOX determination in sewage sludge, underpinning high-confidence environmental analytics and regulatory compliance.

Reference

1. ISO Guide 31 (2015): Reference materials – Contents of certificates.
2. ISO Guide 35 (2017): Reference materials – General and statistical principles.
3. EPA Method 1650 (1988): Organochlorine and Trace Elements by Combustion.
4. DIN 38414-18 (1991): German standard methods for water analysis.
5. ČSN EN ISO 17034 (2017): General requirements for the competence of reference material producers.