Alcohol Determination of Sanitizer Gel in accordance with USP<611> - No. 348

Significance of the Topic

Accurate measurement of ethanol concentration in hand sanitizer gels is essential for ensuring product safety and compliance with regulatory standards such as USP <611>. Reliable quantification supports quality control in pharmaceutical and consumer goods industries.

Objectives and Study Overview

• Establish a gas chromatography method tailored to sanitizer gel matrices.
• Meet USP <611> criteria for ethanol determination.
• Utilize an internal standard to improve accuracy.

Methodology and Instrumentation

• Instrument: Shimadzu Nexis GC-2030 gas chromatograph with AOC-20i Plus autosampler.
• Detector: FID-2030 flame ionization detector.
• Column: SH-624 capillary column (30 m x 0.53 mm i.d., 3 µm film).
• Carrier gas: helium at linear velocity of 34 cm/s.
• Temperature program: 50 °C hold 5 min, ramp 10 °C/min to 200 °C, hold 4 min, total run time 24 min.
• Injection: split mode (1:5), injector at 210 °C, sample volume 0.2 µL using an elastic syringe to maintain injection reproducibility in aqueous matrices.
• Internal standard: acetonitrile.

Sample Preparation

Sanitizer gel samples were diluted in aqueous solution. A split glass insert containing wool was used to improve sample vaporization and peak shape in the autosampler vial.

Main Results and Discussion

The method achieved clear separation of ethanol and internal standard within 24 minutes. Key performance metrics included consistent retention times, linear calibration over the target concentration range, and satisfactory repeatability. The use of an elastic syringe ensured stable sample introduction and improved precision in aqueous samples.

Benefits and Practical Applications

This GC-FID approach provides a robust and reproducible protocol for routine quality control of sanitizer products. It supports regulatory compliance, batch release testing, and troubleshooting in manufacturing environments.

Future Trends and Potential Applications

Advances may include integration with mass spectrometry for enhanced selectivity, high-throughput autosampling systems, and adaptation to other alcohol-based formulations. Automation and miniaturization could further streamline sanitizer analysis in decentralized laboratories.

Conclusion

The developed GC-FID method using a SH-624 column fulfills USP <611> requirements for ethanol determination in sanitizer gels, offering reliable performance for QC laboratories.

References

• Shimadzu Application News G333 (2022) Alcohol Determination of Sanitizer Gel in accordance with USP<611>.