CRM Fluorides (F-) - Aqueous calibration solution ASTASOL® AN90731HIC

Significance of the Topic

Reliable and SI-traceable aqueous calibration solutions for fluoride ions are essential in environmental monitoring, water quality assessment and industrial process control. Certified reference materials (CRMs) provide the benchmark for method validation and interlaboratory comparability in spectrometric and electroanalytical techniques.

Objectives and Study Overview

This certificate describes the preparation, characterization and certification of ASTASOL® AN90731HIC, a fluoride calibration solution. The goal is to supply a high-purity, stable reference material with well-defined uncertainty and traceability for analytical laboratories.

Methodology and Instrumentation

The solution was gravimetrically prepared from 99.99 % pure NaF in ultrapure demineralized water. Key steps include:

• Filtration through a 0.45 µm membrane ultrafilter to protect chromatographic systems
• Verification of fluoride concentration by complexometric titration using NIST SRM 928
• Determination of trace impurities (bromides, chlorides, iodides, nitrites, nitrates, phosphates, sulfates) by ion chromatography for informational purposes

Main Results and Discussion

The certified fluoride concentration is 1000 ± 2 mg/L (expanded uncertainty, k=2) at 20 °C, corresponding to 999 ± 3 mg/kg mass fraction based on measured density (1.0012 ± 0.0005 g/cm³). Trace impurities are below detection limits (<0.02 mg/L), confirming high chemical purity. Homogeneity testing and stability studies ensure performance over a five-year shelf life and a 12-month period after first opening under recommended storage conditions.

Benefits and Practical Applications

ASTASOL® AN90731HIC supports calibration and validation for:

• Atomic spectrometry (AAS, AES, ICP-OES, ICP-MS, IC)
• Molecular absorption spectrometry
• Electroanalytical fluoride determinations

Future Trends and Opportunities

Advancements in CRM development may focus on multi-element and matrix-matched solutions, reduced uncertainty budgets through improved characterization techniques, and expansion into lower concentration ranges to meet emerging analytical demands.

Conclusion

ASTASOL® AN90731HIC delivers a rigorously characterized, SI-traceable fluoride calibration solution with robust stability and homogeneity. It enables accurate, reproducible analytics across diverse instrumental platforms.

Reference

• ISO Guide 31: Reference Materials – Contents of Certificates and Labels
• ČSN EN ISO 17034:2017 – General Requirements for Reference Material Producers
• NIST SRM 928 – Fluoride Standard Reference Material