Sorbitol in Mouthwash Using Accucore 150-Amide-HILIC

Importance of Topic

Polar analytes such as sorbitol and cationic surfactants in pharmaceutical mouthwash formulations require sensitive, interference-free analytical methods for quality control and regulatory compliance. The use of hydrophilic interaction liquid chromatography (HILIC) provides robust retention of highly polar compounds and enables direct injection of samples with minimal preparation.

Objectives and Study Overview

The primary aim was to develop and validate a rapid, isocratic HILIC method for the simultaneous determination of sorbitol and cetylpyridinium in mouthwash. The study evaluated the separation efficiency, peak shape, and detection performance using a combination of refractive index and suppressed conductivity detectors.

Methodology and Instrumentation

• Chromatographic System: Thermo Scientific™ ICS-3000 Ion Chromatography system or UltiMate™ 3000 LC system.
• Columns:
  • Thermo Scientific™ Accucore™ 150-Amide HILIC, 2.6 µm, 3.0 × 150 mm.
  • Thermo Scientific™ Acclaim™ Surfactant Plus, 4.6 × 100 mm.
• Mobile Phase: Isocratic mixture of acetonitrile and aqueous phase containing formic acid and sodium perchlorate.
• Flow Rate: 0.5 mL/min; Column Temperature: 25 °C.
• Injection Volume: 5 µL of mouthwash sample, no sample preparation required.
• Detection:
  • Refractive Index detection for sorbitol quantification.
  • Suppressed conductivity detection with blank subtraction for cetylpyridinium.

Main Results and Discussion

The developed method achieved baseline separation of sorbitol and cetylpyridinium with sharp, symmetric peaks. Sorbitol, present at high concentration levels, was accurately quantified by RI detection, while the suppressed conductivity detector effectively measured cetylpyridinium after blank subtraction. The overall run time was under 20 minutes, demonstrating high throughput capability.

Benefits and Practical Applications

• Fast, isocratic analysis reducing system equilibration time.
• Direct injection without complex sample pretreatment.
• High sensitivity and selectivity for polar and ionic species.
• Applicable for routine quality control of mouthwash formulations in pharmaceutical and cosmetic laboratories.

Future Trends and Potential Applications

• Expansion of HILIC methods to other non-nutritive sweeteners and ionic preservatives.
• Integration with mass spectrometry for enhanced sensitivity and structural elucidation.
• Development of miniaturized, high-throughput platforms for field or on-site testing.

Conclusion

The HILIC-based method on Accucore™ Amide and Acclaim™ Surfactant Plus columns provides a robust, efficient, and user-friendly approach for simultaneous determination of sorbitol and cetylpyridinium in mouthwash products. Its simplicity and reliability make it ideal for routine QC applications.

Reference

• Thermo Fisher Scientific. PB20627_E 10/12S.
• Thermo Fisher Scientific Inc. PB20797_E 05/13S.