Determination of ethanol in hand sanitizers by a self-built headspace device and gas chromatography

Abstract

Introduction: Headspace sampling coupled with gas chromatography (HS-GC) has been proven to be a very useful technique for the determination of volatile and semivolatile components in complex matrices by avoiding tedious sample preparation. In this study, the HS system was fabricated at low cost, exploiting unused GC sensor-heaters. Methods: The accuracy and stability of the self-built HS were evaluated, and the HS-GC-FID system was applied to the determination of ethanol in hand sanitizer gels. The HS operating conditions, including temperature and equilibrium time, were optimized using a central composite face-centered design (CCFC) and MODDE 5.0 software. Samples incubated at 80 °C for 25 min gave the best results with respect to sensitivity and reproducibility (RSD < 3%). Results: The calibration curve showed high linearity (R2 > 0.998) in the range of 0.25 to 2.5% (w/w) ethanol, using acetonitrile 1% (w/w) as an internal standard. The recovery ranged between 104.1 and 108.3% using spiked samples on real matrices. A small survey of 11 commercially available samples collected in the local markets showed that only one of them did not meet the standards set by the FDA.