Ion-Chromatographic Determination of Seven Common Anions in Drinking and Surface Water according to the ISO 10304-1:2007 Standard

Significance of the topic

Effective monitoring of inorganic anions in drinking and surface water is critical to meet regulatory requirements, safeguard public health and ensure water quality. The revised European Drinking Water Directive emphasizes control of ions such as fluoride, chloride, nitrite, bromide, nitrate, phosphate and sulfate. Reliable analytical methods are needed for routine testing in municipal and environmental laboratories.

Study objectives and overview

This work describes a quantitative method for simultaneous determination of seven common anions in various water matrices according to ISO 10304-1:2007. It demonstrates the performance of a novel Shimadzu HIC-ESP ion chromatography system with suppressed conductivity detection and optional UV detection for enhanced nitrite analysis.

Methodology and instrumentation

• Instrument: Shimadzu HIC-ESP IC with CBM-40 controller, DGU-405 degasser, LC-20Ai pump, SIL-20A autosampler, CTO-40S column oven, CDD-10Avp conductivity detector and SPD-40 UV detector (210 nm)
• Column: Shim-pack IC-SA2 (250×4.0 mm, 9 μm) with guard column
• Eluent: 1.8 mmol/L sodium carbonate and 1.7 mmol/L sodium bicarbonate at 1.0 mL/min
• Suppressor: ICDS-40A electrolytic self-regenerating unit at 28 °C cell temperature
• Sample preparation: Filtration through 0.45 μm PET, dilution 1/40 (v/v) with DI water as needed

Main results and discussion

Precision for retention time (≤0.04% RSD) and peak area (≤0.45% RSD) confirms high repeatability. Resolution between fluoride and void peak exceeds USP requirements (R≥1.3). Calibration curves show linearity with R2≥0.9993 across 0.05 to 5 mg/L (0.025 to 5 mg/L for nitrite by UV). Signal-to-noise ratios exceed 12 for all ions and reach 31 for nitrite by UV detection. Method detection limits allow quantification down to 0.025 mg/L for nitrite. Recoveries in fortified samples range from 98% to 110% across diverse matrices. Analysis of tap, dispenser, bottled and surface water samples yielded concentration profiles consistent with expected water quality variations.

Benefits and practical applications

• Compliant with ISO 10304-1 and EU drinking water directives
• High sensitivity and resolution for routine water quality control
• Optional UV detection enhances selectivity for nitrite, bromide and nitrate in challenging matrices
• Robust suppressor design reduces peak dispersion and maintenance requirements

Future trends and potential applications

Expansion of ion chromatography toward mass spectrometry coupling may enable multi-analyte screening in complex matrices. Advances in miniaturized and portable IC systems can support on-site water monitoring. Integration of automated sample preparation and data analytics, including AI-driven evaluation, will streamline high-throughput testing. Sustainable eluent strategies and green suppression technologies are likely to shape future developments.

Conclusion

The Shimadzu HIC-ESP IC system with suppressed conductivity and optional UV detection delivers a sensitive and reliable platform for simultaneous determination of seven key inorganic anions in drinking and surface water. The method meets ISO and pharmacopeia standards, offering robust performance for regulatory compliance and routine laboratory applications.

References

• European Commission. Revised Drinking Water Directive. Accessed January 2021
• European Citizens Initiative Right2Water. Accessed January 2021
• ISO 10304-1:2007. Water quality — Determination of dissolved anions by ion chromatography