Determination of Ethanol in Soft Drinks by Gas Chromatography Using Headspace Single-Drop Microextraction

A simple and a rapid procedure for the gas-chromatographic determination of ethanol in soft drinks is proposed (kvass, grape juice, non-alcoholic beer) based on the headspace microextraction of an analyte into a drop (1 μL) of distilled water located above the surface of the analyzed liquid on the tip of a needle of a standard microsyringe for gas chromatography. The limit of detection for ethanol is (3–6) × 10^–5 vol %, the time of a replicate determination, including headspace extraction, does not exceed 5 min. 2-Propanol, not detected in the beverages, is used as an internal standard. The accuracy of the procedure is confirmed by the added–found method, the relative standard deviation does not exceed 7% at the ethanol concentration in the sample 10^–2 vol %.