Determination of Ethanol In Alcoholic Beverages by Liquid Chromatography Using the UV Detector

Ethanol in certain beverages and in similar solutions may be determined by reversed-phase liquid chromatography (LC) using the UV detector. The mobile phase in this indirect photometric detection technique contains a low concentration of a UV-absorbing compound, such as acetone, that coelutes with the ethanol peak. Several variables such as the choice and concentration of the UV-detection agent are examined regarding their effects on the retention time, magnitude and linearity of peak area, and other aspects of quantitation. Except for filtering to remove particulate matter, samples can be injected without pretreatment. The concentration of ethanol in several types of beverages can be determined with 2% relative standard deviation, calibration is linear to 40% ethanol, and the minumum detectable concentration is 0.1%.