Alcohol Levels Determination in Hand Sanitizers by FTIR

Importance of the Topic

Ensuring correct alcohol content in hand sanitizers is essential for effective disinfection and compliance with health regulations. Rapid, non-destructive testing helps manufacturers and quality control laboratories verify product efficacy and safety without extensive sample preparation.

Aim and Overview

This study presents a complete workflow for identifying and quantifying ethanol and isopropanol levels in hand sanitizers using FTIR spectroscopy on the Cary 630 platform. It covers standard preparation, method development, model calibration, and creation of a routine QC procedure.

Methodology and Instrumentation

Samples were prepared following WHO recommendations: ethanol or isopropanol with glycerol and hydrogen peroxide diluted to volume with water. Ten calibration standards and two independent validation samples were produced for each alcohol type.
Measurement steps included ATR accessory cleaning, background collection, spectral acquisition between 4000 and 650 cm1, and automated data capture via MicroLab software.

Použitá instrumentace

• Agilent Cary 630 FTIR spectrometer with single-reflection diamond ATR module
• MicroLab software suite (Data Collect Only, Quant, Lite)
• Volumetric flasks, single-use pipettes, distilled water, ethanol, isopropanol, glycerol, hydrogen peroxide

Key Results and Discussion

Calibration based on Simple Beers Law yielded linear models with R squared values near 0.99. Ethanol showed characteristic peaks around 1080 and 1045 cm1, while isopropanol exhibited bands near 1160, 1130 and 1105 cm1. A ratio-based model in the fingerprint region (peak height at 950 cm1 to 879 cm1) allowed reliable differentiation between alcohols. Routine QC methods combined identification and quantification components, automatically reporting concentrations only when identification criteria were met.

Benefits and Practical Applications

• Fast, reagent-free analysis with minimal sample handling
• Integrated identification and quantification in a single method
• Robust performance suitable for regulatory compliance and production monitoring

Future Trends and Potential Uses

Advances may include chemometric enhancements for complex formulations, expansion to other active ingredients, remote or automated sampling systems, and high-throughput screening in industrial settings.

Conclusion

The described FTIR ATR approach on the Cary 630 spectrometer provides a validated, efficient solution for precise determination of ethanol and isopropanol content in hand sanitizers, supporting quality assurance in manufacturing and regulatory environments.

Reference

Agilent Technologies Application Guide Analysis of Alcohol Levels in Hand Sanitizer 5994-2827EN 2020