A simple and green method for determination of ethanol in liquors by the conductivity measurement of the uncatalyzed esterification reaction

Abstract

A simple and green procedure for quantifying the ethanol concentration based on the conductometric method and the uncatalyzed esterification reaction was demonstrated. The reaction progress between ethanol and acetic acid was followed by detecting the electrical conductivity, corresponding to the amount of hydrogen ion and acetate anion from acetic acid dissociation. By fixing the concentration of acetic acid, the decrease of conductivity with increasing the ethanol concentration was observed. The inversely linear relation between the conductivity and ethanol concentrations in the range of 0.0–99.9%v/v was successfully obtained. The ethanol content can be efficiently quantified, with good intra-day and inter-day precision (<3.45% RSD). The proposed method was successfully employed for determining the ethanol concentration in liquor samples, validated by the GC method. Therefore, this proposed strategy provides an alternative practical method through conductometry for the quantitative detection of non-electrolytic ethanol solution.