Analysis of Chloride ion and sulfate ion in chondroitin sulfate

Significance of the topic

Accurate determination of counter-ions such as chloride and sulfate in chondroitin sulfate is crucial for ensuring product safety, quality, and compliance with pharmacopeial standards. Reliable ion chromatography methods support pharmaceutical manufacturers and quality control laboratories by providing sensitive, precise, and reproducible analysis of these anions.

Objectives and Study Overview

This application note presents the development and validation of an ion chromatography (IC) method using Shimadzu’s Shim-pack IC-SA2 column for quantifying chloride and sulfate in pharmaceutical grade chondroitin sulfate. The method aligns with Japanese Pharmacopeia requirements and aims to deliver robust separation with high throughput.

Methodology

A dual-eluent gradient was employed: Eluent A composed of 1.7 mmol/L sodium hydrogen carbonate and Eluent B of 1.8 mmol/L sodium carbonate. The flow rate was set at 0.9 mL/min with a column temperature of 30 °C. Samples (25 µL injection) were analyzed under suppressed conductivity detection to achieve selective measurement of anions.

Used Instrumentation

• Analytical column: Shim-pack IC-SA2 (250 mm × 4.0 mm I.D., 9 µm)
• Guard column: Shim-pack IC-SA2(G) (10 mm × 4.0 mm I.D., 9 µm)
• Suppressor: Suppressed conductivity detection system
• Eluent delivery: Binary pump compatible with carbonate/bicarbonate eluents
• Sample vials: Polypropylene, Shimadzu P/N 228-31537-91

Main Results and Discussion

The method achieved clear baseline separation of chloride (peak 1) and sulfate (peak 2). Retention times were consistent, with relative standard deviations below 1.5% for replicate injections. The suppressor system provided low background conductivity and high signal-to-noise ratios, ensuring quantification limits suitable for pharmacopeial specifications.

Benefits and Practical Applications

• High specificity and sensitivity for anion analysis
• Robustness across routine QC workflows
• Minimal sample preparation reduces analysis time
• Compliance with Japanese Pharmacopeia standards

Future Trends and Potential Applications

Emerging directions include coupling IC with mass spectrometric detection for enhanced selectivity, implementation of shorter columns for faster turnaround, and exploring microfluidic IC systems for reduced solvent consumption and increased throughput.

Conclusion

The presented IC method on the Shim-pack IC-SA2 column offers a reliable, reproducible, and efficient approach for chloride and sulfate determination in chondroitin sulfate, supporting pharmaceutical quality control and regulatory compliance.

References

1. Shimadzu Corporation. Application News an_01-00414 (JP), First Edition: Aug. 2023.