Ethanol was extracted from samples by headspace solid-phase microextraction (HS-SPME) using a fibre coated with 85-μm polyacrylate film (Supelco, Bellefonte, PA, USA). Before use, the fibre was conditioned following the instructions of the manufacturer. An aliquot (500 mg) of each sanitising gel sample (1–7) and calibration standards was transferred to an 8-ml screw-capped amber vial with a PTFE-lined silicone septum. The vial was thermostated for 1 min at 30 °C before SPME extraction. The SPME fibre was inserted into the headspace of the vial through the septum on the screw cap, then it was exposed to the headspace of the vial for 20 s at 35 °C. After the extraction, SPME fibre was removed from the vial and inserted into the gas chromatograph (GC) injection system for the analysis.