Analysis of Fatty Acid Content Ratios in Polysorbate 80

Significance of the Topic

Polysorbate 80 is widely employed in pharmaceutical, food and cosmetic formulations. Accurate determination of its fatty acid composition is crucial for quality control, ensuring consistency, safety and regulatory compliance.

Objectives and Study Overview

• Establish a gas chromatographic method with flame ionization detection to quantify fatty acid methyl esters (FAMEs) in Polysorbate 80.
• Determine the relative content ratios of major fatty acids present in the sample.

Methodology and Instrumentation

The fatty acids in Polysorbate 80 are methylated to form FAMEs and analyzed by GC-FID. Chromatographic separation is achieved on a polar wax column under a temperature program from 80 °C to 220 °C at 10 °C/min. Helium is used as the carrier gas at a linear velocity of 50 cm/s. Injection is performed in split mode (1:20) with a 1 µL sample volume.

Used Instrumentation

• Gas chromatograph: Shimadzu GC-2010 Plus AF with AOC-20i autosampler
• Column: SH-PolarWax, 30 m × 0.32 mm I.D., 0.5 µm film thickness
• Detector: Flame ionization detector (FID) at 250 °C
• Injector temperature: 250 °C

Main Results and Discussion

The method successfully separated and identified eight FAMEs: methyl myristate, methyl palmitate, methyl stearate, methyl arachidate, methyl oleate, methyl cis-11-eicosenoate, methyl behenate and methyl lignocerate. Baseline separation and consistent retention times were achieved, allowing precise calculation of fatty acid ratios in Polysorbate 80.

Benefits and Practical Applications

• The protocol offers a reliable approach for routine quality control of polysorbate-based excipients.
• Applicable in pharmaceutical, food and cosmetic industries to verify raw material consistency and meet regulatory standards.

Future Trends and Application Possibilities

Advancements may include coupling GC with mass spectrometry for enhanced structural identification, implementation of faster temperature ramps or shorter columns for higher throughput, the use of greener carriers and solvents, and automation to support high-throughput laboratory workflows.

Conclusion

The developed GC-FID method on an SH-PolarWax column provides a robust, reproducible and efficient tool for determining fatty acid content ratios in Polysorbate 80, supporting quality assurance in critical applications.

Reference

• Application News G285, Shimadzu Corporation, First Edition September 2022.