CRM Sulfates (SO42-) - Aqueous calibration solution ASTASOL® AN90781HIC

Importance of Topic

This certificate describes a high‐purity aqueous sulfate calibration standard designed to ensure reliable quantification of sulfate ions in water samples under various analytical techniques.

Objectives and Study Overview

The primary aim is to provide a certified reference material (CRM) with well‐defined sulfate concentration and traceability to SI units, facilitating calibration and method validation in routine and research laboratories.

Methodology and Instrumentation

The solution is prepared gravimetrically from (NH4)2SO4 with 99.9999% purity, ensuring direct traceability to the kilogram. Sulfate content is characterized by precipitation as BaSO4 and verified against NIST SRM 3181. Trace anions are measured by ion chromatography. The solution is filtered through a 0.45 µm membrane to protect analytical columns. Density is determined at 20 °C to convert concentration to mass fraction.

• Gravimetric preparation and BA gravimetry
• Verification with SRM NIST 3181
• Ion chromatography for impurity profiling
• Membrane ultrafiltration (0.45 µm)
• Density measurement at 20 °C

Main Results and Discussion

The certified sulfate concentration is 1000 ± 2 mg/L (1001 ± 3 mg/kg). All common anionic impurities (Br–, Cl–, F–, I–, NO2–, NO3–, PO43–) are below the detection limit (< 0.02 mg/L). Homogeneity and stability tests confirm performance over a five‐year shelf life when stored between 5–30 °C. Detailed handling instructions minimize contamination and preserve certified values.

Benefits and Practical Applications

This CRM supports calibration and validation across multiple techniques (AAS, AES, ICP‐OES, ICP‐MS, IC, molecular absorption, electroanalysis). Its low uncertainty and high purity improve data quality in environmental monitoring, industrial QA/QC, and research settings.

Future Trends and Opportunities

As analytical demands shift toward ultra‐trace determinations, future CRMs may feature tighter uncertainty budgets and multi‐analyte formats. Integration with automated calibration systems, digital certificates, and advanced characterization techniques (e.g., hyphenated mass spectrometry) will further enhance usability and traceability.

Conclusion

ASTASOL® AN90781HIC provides a robust, SI‐traceable sulfate standard with well‐characterized concentration, minimal impurities, and proven stability, ensuring accurate calibration and validation for diverse laboratories.

Reference

Analytika, spol. s r.o. Certificate for ASTASOL® AN90781HIC, Certified Reference Material No. AN90781HIC, Version 01, 17 October 2022.