QCM - Loam, elevated analyte levels - METRANAL® 34

Importance of the Topic

Quality control materials are essential for ensuring reliable and comparable analytical data in soil analysis. The METRANAL® 34 loam reference material supports accurate quantification of trace elements and operationally defined fractions, driving confidence in environmental monitoring, agricultural chemistry, and regulatory compliance.

Objectives and Overview

This declaration outlines the certification of METRANAL® 34 as a quality control material for loam with elevated analyte levels. The document defines the intended use of the material for internal and external quality control charts, inter-laboratory comparisons, and bias estimation, rather than direct calibration traceability.

Methodology and Material Preparation

• The reference values were established by 5–25 ISO 17025 accredited laboratories using validated analytical protocols.
• Total element contents were determined on samples dried at 105 °C, while extractable fractions were obtained by aqua regia digestion according to ISO 11466.
• Uncertainties represent the half-width of a 95% confidence interval.
• Radiation sterilization (25 kGy) was applied to stabilize the material.

Main Results and Discussion

• Total concentrations (mg/kg) and aqua regia extractable fractions are reported for arsenic through zinc with associated measurement uncertainties.
• The material’s oxide composition was characterized, showing dominant SiO2 (64.35%) alongside Al2O3, Fe2O3, MgO and other major oxides.
• Comparison of total versus extractable contents highlights the fractionation behavior of key trace elements in loam matrices.

Benefits and Practical Applications

• Provides a stable benchmark for monitoring analytical performance in soil testing laboratories.
• Supports method validation, quality assurance, and proficiency testing across different analytical platforms.
• Facilitates bias assessment in routine determination of total and aqua regia extractable elements.

Future Trends and Applications

Ongoing developments in soil reference materials aim to cover broader concentration ranges and diverse matrix types, including organic-rich soils and contaminated site materials. Integration with advanced speciation and imaging techniques will further enhance the applicability of such materials in environmental risk assessment and regulatory frameworks.

Conclusion

METRANAL® 34 serves as a robust quality control resource for total and operationally defined elemental analysis in loam matrices. Its well-characterized composition and accredited certification underpin reliable QA/QC procedures and inter-laboratory comparability.

No formal references were included in the original declaration.