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Leveraging Hydrogen Bond-Induced Peak Shifting to Determine Alcohol Concentration in Suspect Gel Hand Sanitizers
Hannah LaRoy1, Michael Thatcher1, Lisa Lorenz1
1National Forensic Chemistry Center, U.S. Food and Drug Administration, Cincinnati, Ohio, 45237 USA.
Applied Spectroscopy
|June 26, 2025
Summary
Portable infrared and Raman spectroscopy offer rapid screening for alcohol-based hand sanitizers, detecting adulteration and misbranding effectively. This method enhances regulatory enforcement and consumer safety by quickly identifying non-compliant products.
Area of Science:
- Analytical Chemistry
- Spectroscopy
- Regulatory Science
Background:
- Alcohol-based hand sanitizers are crucial for public health.
- Ensuring product quality and accurate alcohol content is vital for efficacy.
- Current methods for verifying alcohol content can be time-consuming.
Purpose of the Study:
- To assess the feasibility of portable infrared and Raman devices for rapid screening of alcohol-based hand sanitizers.
- To detect potential adulteration or misbranding in hand sanitizer products.
- To develop a screening workflow for expedited analysis.
Main Methods:
- Utilized portable infrared and handheld Raman spectroscopy to analyze alcohol-based hand sanitizers.
- Estimated alcohol potency by analyzing hydrogen bond-induced peak shifting in alcohol-water mixtures.
- Developed calibration equations based on characteristic peak ratios for concentration determination.
Main Results:
- Achieved linear responses for alcohol concentration (v/v%) between 30%-100% (infrared) and 40%-100% (Raman).
- Average errors in alcohol concentration estimation were 1.6% (infrared) and 2.4% (Raman) compared to GC-FID.
- All 21 violative samples identified by rapid screening were confirmed by GC-FID; 3 non-violative samples were also confirmed.
Conclusions:
- Portable infrared and Raman spectroscopy are feasible for rapid screening of alcohol-based hand sanitizers.
- This screening method can efficiently identify non-compliant products, supporting regulatory enforcement and consumer safety.
- The workflow is suitable for field deployment at various logistical points for expedited product analysis.
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