Low-cost bench-scale methodology for ethanol quantification

Abstract

Ethanol quantification is an essential step in both academic research and industrial applications. Various methodologies are used for this purpose, but most are expensive. This study aims to establish a simple and inexpensive method for ethanol quantification, employing potassium dichromate as the oxidizing agent and UV-Visible spectrophotometry as the detection technique. Potassium dichromate in an acidic medium and hydroalcoholic standard solutions were used to produce a colored chromium (III) complex, which is quantified by measuring absorbance at 600 nm. Two calibration curves were constructed: one with the ethanol concentration expressed in % (v/v) and the other in g/L, with the analytical parameters evaluated being linearity, limit of detection (LOD), limit of quantification (LOQ), and reproducibility. Both calibration curves exhibited high coefficients of determination (R²), confirming the method’s linearity. For ethanol concentration expressed in % (v/v), the LOD and LOQ values were 0.60% and 1.81%, respectively. For ethanol concentration expressed in g/L, the LOD was 0.14 g/L and the LOQ was 0.43 g/L. Overall, the adoption of spectrophotometric methods offers a suitable solution for laboratories with technical and financial limitations, providing accessible methodologies with broad practical applicability and low cost.