Determination of Ethanol in Beer by Direct Injection Gas Chromatography: A Comparison of Six Identical Systems

Abstract

Six identical gas chromatographic (GC) systems from the same manufacturer were evaluated for the determination of ethanol in beers. Each system was assessed for detector linearity and drift using standard ethanol solutions. Repeatability (rss) of each machine, repeatability (rss) of the GC method and reproducibility (Rss) of the method over a range of ethanol concentrations (1-11% V/V) was determined using commercial beers. All six instruments were linear over the ethanol range 0-12% V/V and were in good agreement. Drift of the machines was negligible over the period of the analysis. Over the ethanol range 0.95 to 6.32% V/V the repeatability (res) and reproducibility (Rss) values were 0.050 and 0.083 respectively. Over the ethanol range 9.48 to 11.15% V/V the repeatability (rss) and reproducibility (Rss) values were 0.153 and 0.227 respectively. Comparison of the precision values and those obtained in a recent IOB Analysis Committee Collaborative1 for the determination of ethanol by gas chromatography showed no significant differences between the two methods. The reported method is suitable for determination of ethanol in beers.

A New Amperometric Carbon Paste Enzyme Electrode for Ethanol Determination

“…For ethanol determination, various instrumental methods such as gas chromatography (Clarkson et al 1995), liquid chromatography coupled with absorbance or fluorescence detection (Vitrac et al 2002), spectrophotometry (Lázaro et al 1986;Segundo and Rangel 2002) or enzymatic test-kits have been reported. However, these methods are laborious, expensive, time-consuming, and complex to perform.…”