title: A simple strategy for determining ethanol in all types of alcoholic beverages based on its on-line liquid-liquid extraction with chloroform, using a flow injection system and Fourier transform infrared spectrometric detection in the mid-IR.
abstract: 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 877cm(-1)(,) corrected by means of a baseline established between 844 and 929cm(-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.
authors.affiliation: "Laboratorio de Espectroscopia Molecular (LEM)", Departamento de Química, Facultad de Ciencias, Universidad de Los Andes (ULA), Mérida, Venezuela.
authors.forename: Máximo
authors.initials: M
authors.lastname: Gallignani
authors.forename: Carlos
authors.initials: C
authors.lastname: Ayala
authors.forename: Maria Del Rosario
authors.initials: Mdel R
authors.lastname: Brunetto
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Burguera
authors.forename: Marcela
authors.initials: M
authors.lastname: Burguera