Analysis of Anions

Importance of the topic

Ion chromatography is a cornerstone technique in environmental and water analysis, allowing precise determination of inorganic anions at trace levels. Accurate quantification of species such as fluoride, nitrate and sulfate is essential for regulatory compliance, pollution monitoring and safeguarding public health.

Objectives and study overview

This application note presents a robust method for simultaneous separation and detection of nine common anions using Shimadzu’s Shim-pack IC-SA2 column. The goal is to demonstrate resolution, sensitivity, and runtime efficiency for routine quality control and environmental laboratories.

Methodology

An isocratic suppressed conductivity ion chromatography approach was adopted. A carbonate/bicarbonate mobile phase enables effective elution of both monovalent and multivalent anions. Suppression reduces background conductivity, improving signal-to-noise ratios.

Used instrumentation

• IC system: Prominence HIC-SP
• Analytical column: Shim-pack IC-SA2 (250 mm × 4.0 mm I.D., 9 µm)
• Mobile phase: 12 mmol/L NaHCO₃ and 0.6 mmol/L Na₂CO₃
• Flow rate: 1.0 mL/min
• Column temperature: 30 °C
• Injection volume: 50 µL
• Detector: Suppressed conductivity (CDD-10Avp)

Main results and discussion

The method achieved baseline separation of nine anions—including fluoride, acetate, formate, chloride, nitrite, bromide, nitrate, phosphate and sulfate—within 18 minutes. Resolution exceeded regulatory requirements, and repeatability was better than 1 % RSD for retention times and peak areas. Sensitivity permitted detection limits below 0.1 mg/L for most analytes.

Benefits and practical application

• Rapid, high-throughput analysis ideal for routine water quality testing
• Low background noise and high sensitivity via suppressor technology
• Robust performance under isocratic conditions simplifies method maintenance
• Applicability to environmental monitoring, drinking water certification and industrial process control

Future trends and possibilities of use

Emerging developments include coupling ion chromatography with mass spectrometry for enhanced selectivity, miniaturized high-pressure systems for field deployable analysis, and the use of greener mobile phases. Automated calibration and data interpretation using AI-driven software promise to further streamline workflows.

Conclusion

The Shim-pack IC-SA2 combined with the Prominence HIC-SP system delivers reliable, efficient separation and quantification of key inorganic anions. Its reproducibility, sensitivity and moderate runtime make it a valuable tool for both environmental laboratories and industrial quality assurance.

References

1. Shimadzu Corporation. ERAS-1000-0379: Ion Chromatography (IC) Shim-pack Series, First Edition, October 2022.