Rapid spectroscopic measurement of methanol in water-ethanol-methanol mixtures

Abstract

The paper is focused on the Raman spectroscopic analysis of methanol content in water-ethanol-methanol mixtures as this kind of mixture chemically closely relates to alcoholic drinks. Counterfeit alcoholic drinks represent losses to the economy, but especially can cause serious health risks starting from nausea, to blindness, and even death. Extensive methanol poisonings were reported in last decades in number of countries worldwide. A set of water-ethanol-methanol mixtures with a range of concentrations of methanol from 0 % to 100 % was prepared to obtain the calibration dataset, needful for quantitative assessment. Based on calibration data, test samples and alcoholic beverages were evaluated. Raman spectroscopy is used especially because of this method's benefits as specific vibrational fingerprint, direct measurement through the bottles, no need of additional chemicals and fast response. The study confirms the rapid and accurate analysis complying with safety limits set by methanol spirits legislation.