In this work, a simple strategy for the determination of ethanol in all types of alcoholic beverages using Fourier transform infrared spectrometric
detection has been developed. The methodological proposal includes the quantitative on-line liquid–liquid extraction of ethanol with chloroform,
through a sandwich type cell equipped with a PTFE membrane, using a two-channel manifold; and direct measurement of the analyte in the organic
phase, by means of Fourier transform infrared spectrometry. The quantification was carried out measuring the ethanol absorbance at 877 cm−1
,
corrected by means of a baseline established between 844 and 929 cm−1. The procedure, which does not require any sample pretreatment (except
for the simple degassing of beer and gassy wine samples, and a simple dilution of spirits with water), was applied to determine ethanol in different
alcoholic beverages such as beers, wines and spirits. The results obtained highly agree with those obtained by a derivative FTIR spectrometric
procedure, and by head space-gas chromatography with FID detection. The proposed method is simple, fast, precise and accurate. Moreover, it
can be easily adapted to any infrared spectrometer equipped with a standard transmission IR cell, and provides attractive analytical features, which
are comparable to, or better than those offered by other published methods. In consequence, it represents a valid alternative for the determination
of ethanol in alcoholic beverages, and could be suitable for the routine control analysis.