Differential-pulse polarographic microdetermination of ethanol and its application to beer analysis

Ethanol, after in situ derivatization to ethyl dithiocarbonate under phase-transfer catalysis, was determined in aqueous solution by differential-pulse polarography. A supporting electrolyte of NH4Cl—KH2PO4—NaOH containing eosin was found to be essential in this determination. For the microdetermination of ethanol, this method was proved to be precise, and the detectionlimit was 0.02% or 0.02 mg (absolute amount of ethanol). The viability of the proposed method for beer analysis has also been established.