Analysis of Methanol in Ethanol-based Sanitizer - No. 355

Importance of the Topic

Hand sanitizers based on ethanol are widely used for infection control, but contamination with methanol can pose serious health risks. Reliable analytical methods are essential to detect trace methanol and guarantee product safety and regulatory compliance.

Study Objectives and Overview

• Establish a gas chromatography method to quantify methanol in ethanol-based sanitizers.
• Demonstrate applicability to both liquid and gel sanitizer formulations.

Methodology and Instrumentation

This study utilized gas chromatography with flame ionization detection (GC-FID). Separation employed an SH-624 capillary column (30 m × 0.53 mm, 3 µm film) under the following conditions:

• Column temperature program: 40 °C for 5 min, ramp at 5 °C/min to 90 °C, hold for 2 min (total 17 min).
• Injection: direct 0.2 µL at 150 °C via WBI-2030 inlet.
• Carrier gas: helium at constant 3.00 mL/min.
• FID settings: detector at 150 °C, H₂ flow 32 mL/min, make-up He 24 mL/min, air 200 mL/min.

Main Results and Discussion

• Baseline separation of methanol, acetaldehyde, and ethanol achieved within 17 minutes.
• Detection limits reached 16 ppm for liquid samples and 630 ppm for gel samples after a 40× dilution.
• Calibration followed Japanese Industrial Standard JIS K8101 using certified reference solutions.
• Chromatograms confirmed high specificity and reproducibility for both matrices.

Benefits and Practical Applications

• Rapid, sensitive quantification enhances quality control workflows.
• Minimal sample preparation via direct injection reduces analysis time and risk of contamination.
• Versatile applicability to various sanitizer types supports manufacturing and QA/QC laboratories.
• Ensures compliance with safety regulations and protects consumer health.

Future Trends and Potential Applications

• Automation of sample introduction for high-throughput screening in production environments.
• Extension of the method to detect additional volatile impurities in alcohol-based products.
• Coupling GC with mass spectrometry for confirmatory analysis and broader contaminant identification.
• Implementation in regulatory monitoring programs to enforce safety standards.

Conclusion

The presented GC-FID method using an SH-624 column offers a fast, robust, and sensitive approach to detect methanol in ethanol-based sanitizers. Its simplicity and reliability make it well suited for routine quality control to safeguard public health.

References

• Application News G337, Shimadzu Corporation, First Edition: Sep. 2022.