Direct estimation of ethanol as a negative peak from alcoholic beverages and fermentation broths by reversed phase-HPLC

A relatively simple and straightforward technique utilizing reversed phase liquid chromatography with a PDA-UV detector was used for the detection and quantification of ethanol. Samples of alcoholic beverages and fermentation broths were injected without any prior chemical pre-treatment or structural modification. The C18 column was equilibrated with water as a mobile phase having a high UV absorbing compound, acetone, added in an optimized percentage. Ethanol when injected resulted in a negative peak within 4 minutes of runtime, and the absolute area/height of the peak was used for quantification. The method was validated for linearity with the detection ranging from 0.1-100% v/v. Intra-day and inter-day precision experimental results were within acceptable limits. The accuracy and repeatability of this method can reduce the dependency of using specific columns and detectors for the analysis of ethanol. Direct injection of alcoholic samples/broths into a RP-HPLC (with a PDA-UV detector) system to quantify ethanol directly as a negative peak. The kind of peak pair depends on the ethanol concentration as described in the article.