Gas Chromatography (GC) - Quality Testing — Ethanol in Hand Sanitizers

Significance of the Topic

In the context of global health measures against COVID-19, ensuring the quality and safety of alcohol-based hand sanitizers is critical. Regulatory authorities such as the WHO and CDC require products to contain at least 60 % ethanol or 70 % isopropanol. Moreover, pharmacopeial standards demand strict control of toxic impurities in ethanol. Gas chromatography (GC) provides a robust solution for rapid and precise quantification of ethanol content and impurity profiling in hand sanitizers.

Objectives and Study Overview

This study demonstrates the use of the Shimadzu Nexis GC-2030 system for:

• Determination of ethanol concentration in alcohol-based hand sanitizers.
• Separation and quantification of trace impurities including methanol, acetaldehyde, acetal, benzene, and other volatiles.
• Verification of compliance with national and international standards (e.g., GB/T 26373-2010, European Pharmacopoeia 10.0).

Methodology

Samples were introduced via split injection (11 : 1 or 20 : 1) at 250 °C inlet temperature. The column oven program began at 40 °C (12 min hold), ramped to 240 °C at 10 °C/min with a 10 min hold. Separation employed SH-Rt™-Q-BOND (30 m × 0.53 mm, df 20 μm) or SH-Rtx™-624 (30 m × 0.32 mm, df 1.8 μm) capillary columns. Detection was carried out using flame ionization (FID) and thermal conductivity (TCD) detectors at 260 °C. Resolution between key early eluting peaks (methane, methanol, ethanol) exceeded Rs > 1.5.

Instrumentation Used

• Shimadzu Nexis GC-2030 with Advanced Flow Controller (AFC)
• Detector types: FID and TCD
• Columns: SH-Rt™-Q-BOND (30 m, 0.53 mm ID, 20 μm) and SH-Rtx™-624 (30 m, 0.32 mm ID, 1.8 μm)
• Split/splitless injector with temperature control

Main Results and Discussion

Ethanol concentrations in tested hand sanitizers were found within the required 70–80 % range. Impurity levels were quantified as follows: methanol ≤0.02 %, acetaldehyde + acetal ≤0.001 %, benzene ≤0.0002 %, and other volatiles ≤0.03 %, meeting pharmacopeial limits. Chromatograms exhibited baseline separation of target analytes, ensuring accurate quantification. The Nexis GC-2030 system demonstrated excellent sensitivity and repeatability across replicate injections.

Benefits and Practical Applications

• Fast, reliable ethanol and impurity analysis for QC laboratories.
• Compliance verification with international hygiene standards.
• High throughput enabled by rapid oven programming and robust split injection.
• Versatile configuration for different sample matrices and carrier gases.

Future Trends and Applications

Advances in detector technology (e.g., bidirectional FID, micro-flame sensors) and automation will further enhance GC performance. Coupling GC with mass spectrometry (GC-MS) can expand impurity profiling to novel contaminants. Integration with laboratory information management systems (LIMS) and AI-driven data analysis will streamline quality control workflows and real-time batch release.

Conclusion

The Shimadzu Nexis GC-2030 platform offers a powerful solution for the quality assessment of ethanol-based hand sanitizers. Its high sensitivity, reproducibility, and flexibility make it ideal for meeting stringent regulatory requirements and ensuring consumer safety.

References

1. World Health Organization, WHO Guidelines on Hand Hygiene in Health Care, 2009.
2. U.S. Centers for Disease Control and Prevention, Hand Hygiene Recommendations, 2020.
3. GB/T 26373-2010, Hygienic Standard for Alcohol Disinfectants, National Standard of the People’s Republic of China.
4. European Pharmacopoeia 10.0, Monograph on Ethanol, Council of Europe.