High-performance liquid chromatography with real-time Fourier-transform infrared detection for the determination of carbohydrates, alcohols and organic acids in wines

The coupling of high-performance liquid chromatography (HPLC) with Fourier-transform infrared spectroscopy (FTIR) is presented as a new and versatile tool for the direct determination of the main components of wine, which are glucose, fructose, glycerol, ethanol, acetic, citric, lactic, malic, succinic and tartaric acid. An ion-exchange resin based column (counterion: HC) was employed as the stationary phase and 0.005 M sulfuric acid as the mobile phase. FTIR detection in the spectral region from 1600 to 900 cm(-1) was performed in a 25-mu m flow cell without elimination of the solvent. Characteristic FTIR spectra were obtained subsequent to the injection and separation of 2 mg/ml of each component. The average standard deviation of the investigated compounds was found to be 66 mu g/ml in standard solutions containing 1-10 mg/ml of the analyte. The method was furthermore applied to real wine samples taken from a round robin test. An average deviation of 0.16 mg/ml from the external reference data was obtained. (C) 1998 Elsevier Science B.V. All rights reserved.