University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Classification: Beverage -> alcoholic -> spirit

Citations 5

"Gas Diffusion Dilution Flow Injection Method For The Determination Of Ethanol In Beverages Without Sample Pretreatment"
Anal. Chim. Acta 1990 Volume 234, Issue 1 Pages 213-220
Wolfgang Künnecke and Rolf D. Schmid

Abstract: Sample was injected into water as carrier stream and passed to a gas diffusion unit, in which ethanol passed through a membrane into a stream of 0.1 M phosphate buffer (pH 7.5). This solution was passed through a column containing immobilized alcohol oxidase, and the H2O2 produced was detected at a platinum working electrode at 700 mV vs. Ag - AgCl. The limit of detection was 6 ppm or 0.1 mM ethanol (coefficient of variation 5.2%, n = 15 to 20), and up to 60% ethanol could be determined, depending on the membranes used. The coefficient of variation was generally 0.2 to 0.7%. Up to 180 samples h-1 could be analyzed. The operational half-life of the immobilized enzyme was 8000 injections in 44 h. The method was applied to beer, wine, spirits and pharmaceuticals.
Ethanol Electrode Gas diffusion Membrane Immobilized enzyme

"Determination Of Ethanol Using Flow Injection Enthalpimetry"
Analyst 1988 Volume 113, Issue 2 Pages 359-360
Walace A. de Oliveira and Celio Pasquini

Abstract: Flow injection enthalpimetry was carried out by using the apparatus described previously (Anal. Chim. Acta, 1984, 156, 307). For the determination of ethanol in fuel-grade ethanol, both the carrier and diluent solution were anhydrous ethanol. Samples (100 µL) were introduced directly into the flow manifold (illustrated) and the resulting enthalpimetric peaks (from the heat of dilution of ethanol) were compared with those of standard solution. Results agreed well with those from a pyknometric method. For the determination of ethanol in wines and spirits, water was used as diluent and carrier and samples were distilled before analysis. The precision for ethanol concentration. of 6 to 12% ranged from 0.03 to 0.1%.
Ethanol Enthalpimetry Method comparison

"Vapor Generation Fourier Transform Infrared Direct Determination Of Ethanol In Alcoholic Beverages"
Analyst 1996 Volume 121, Issue 7 Pages 923-928
Amparo Pérez-Ponce, Salvador Garrigues and Miguel de la Guardia

Abstract: A procedure is proposed for the direct determination of ethanol in alcoholic beverages. The method is based on the injection of small volumes of untreated samples into a heated Pyrex glass reactor in which, at a temperature between 80 and 100°C, the ethanol is volatilized and introduced by means of a nitrogen carrier flow into a gas cell of an FTIR spectrometer. The measurement of the area of the flow injection recording, obtained from the absorbance of the transient signals, in the wavenumber range between 1150 and 950 cm-1, allows the direct quantification of ethanol without water background problems and free from interferences from sugars, providing a limit of detection of 0.02% v/v and typical RSDs between 0.11 and 0.5% for five analyzes of the same sample containing between 5 and 30% v/v ethanol. The sampling frequency of the method is 51 h-1 and accurate results were obtained for different types of alcoholic beverages, from low-alcohol beers to wines and spirits.
Ethanol Spectrophotometry Gas phase detection Interferences

"Alcohol Electrodes In Beverage Measurements"
Anal. Lett. 1994 Volume 27, Issue 15 Pages 3027-3037
Rebelo, M.J.F.;Compagnone, D.;Guilbault, G.G.;Lubrano, G.J.

Abstract: Alcoholic beverage (50-200 µL) was added to 5 mL 0.1 M phosphate buffer of pH 8 (or to 200 µL of diluted buffer for beverages of >20% alcohol content) and a peroxide system alcohol sensor was dipped in the solution with stirring. The steady state current was measured and the background current was subtracted. The calibration graph was linear for 50-700 mg/dl of ethanol; the RSD (n = 3-5) was 0.2-0.84%. The electrode was used in a wall jet mode FIA system. Beverages diluted in 0.1 M phosphate buffer of pH 8 (100 µL) was injected into a phosphate buffer carrier stream at 1 ml/min. The calibration graph was linear for 60-300 mg/dl of ethanol with RSD (n = 10) of 0.4%. The results from the analysis of wines, beers, liqueur, port and vodka were compared with those obtained by the Sigma ethanol test kit. The batch method results agreed well with those reported by the beverage manufacturers.
Ethanol Electrode Steady state Method comparison

"Spectrophotometric Flow Injection Determination Of Ethanol In Distilled Spirits And Wines Involving Permeation Through A Silicon Tubular Membrane"
Anal. Sci. 1998 Volume 14, Issue 5 Pages 1005-1008
Ivanildo L. MATTOS, Raquel P. SARTINI, Elias A. G. ZAGATTO, Boaventura F. REIS and Maria Fernanda GINÉ

Abstract: A concentric tubing reactor comprising an inner silicone tube and an outer polyethylene tube was assembled in a manifold for flow injection determination of ethanol in beverages. The number of potential interferents was restricted by mol. size, and permeation and chemical reaction are allowed to occur along the entire chemical path. For a typical sample with an ethanol content of 40.3%, the relative standard deviation (n=7) was 3.7%.
Ethanol Spectrophotometry Silicone membrane Permeation Tubular membrane Interferences