Municipal drinking water analysis by fast ion chromatography

Significance of the topic

Ion chromatography is a critical analytical technique for monitoring inorganic anions in various water sources, ensuring compliance with regulatory standards for drinking water safety.

Objectives and study overview

This study demonstrates a rapid five-minute IC method for the determination of seven common inorganic anions in municipal drinking water using a compact Dionex Inuvion system coupled with a Dionex IonPac AS22-Fast-4μm column.

Methodology and instrumentation

The analysis employed degassed deionized water, municipal drinking water samples, and a combined seven anion standard. Instrumentation included:

• Dionex Inuvion IC system
• Thermo Scientific Dionex AS-DV autosampler with 5 mL PolyVials and filter caps
• Dionex IonPac AS22-Fast-4μm column set
• Electrolytically regenerated suppressor (AERS 500 Carbonate, 4 mm)
• Suppressed conductivity detection and Chromeleon CDS software v7.3.2

Eluent was 4.5 mM Na2CO3/1.4 mM NaHCO3 at 2.0 mL/min, injection volume 10 µL, column temperature 30 °C, system pressure ~1,800 psi.

Main results and discussion

The five-minute method achieved baseline separation of fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate. Analysis of a drinking water sample indicated fluoride 0.6 mg/L, chloride 9.6 mg/L, nitrite 0.1 mg/L, nitrate 1.2 mg/L, phosphate 0.2 mg/L, and sulfate 16.5 mg/L, all within U.S. EPA regulatory limits.

Benefits and practical applications

The rapid analysis improves sample throughput and supports routine compliance monitoring of drinking and environmental waters. The integrated system offers simplified setup, robust performance, and efficient operation in QA/QC laboratories.

Future trends and opportunities

Advances may include further miniaturization, automation of sample handling, expansion to other analyte classes, coupling with mass spectrometry for enhanced sensitivity, and broader field applications for on-site monitoring.

Conclusion

The Thermo Scientific Dionex Inuvion IC system with IonPac AS22-Fast column enables reliable, high-throughput determination of inorganic anions in drinking water within five minutes, facilitating regulatory compliance and operational efficiency.

References

1. National Primary Drinking Water Regulations (Accessed May 31, 2023).
2. U.S. EPA Method 300.1: The Determination of Inorganic Anions in Water by Ion Chromatography; rev 1.0; U.S. EPA, Office of Water: Cincinnati, OH, 1997 (Accessed May 31, 2023).
3. Inorganic Anions Analysis by EPA 300.0 & 300.1 (Accessed May 31, 2023).
4. The Dionex IonPac AS22-Fast-4μm IC Columns (Accessed May 31, 2023).
5. Thermo Scientific Application Brief 120: Municipal Drinking Water Analysis by Fast IC; Sunnyvale, CA, USA, 2011.