Alcohols in alcohol

The methanol and ethanol contents of distilled alcoholic drinks have been determined simultaneously by Raman spectroscopy. Ethanol, of course, is an essential component in these beverages but allow methanol in too and you are in trouble. It is highly toxic and can cause severe problems like vertigo, blindness and death. Unfortunately, methanol is often used by unscrupulous criminal gangs to produce illicit spirits which people will buy cheaply "as a bargain."

Although many published methods exist to measure the levels of methanol and ethanol in alcoholic drinks, they cannot be measured at the same time in the same experiment, unless preceded by chromatographic separation. So, Turkish researchers have turned to Raman spectroscopy to provide a rapid, single method for both alcohols. Their efforts are described in the Journal of Raman Spectroscopy.

The total analysis time for both methanol and ethanol is less than 30 seconds, including sampling, measurement and calculations which is faster than published procedures for either of the two compounds. It eliminates the need for chromatography while providing good sensitivity with detection limits of 1.2 and 3.4 mM for ethanol and methanol, respectively.

In tests on 23 samples of whisky, gin, vodka and raki bought in a local Turkish market, no methanol was found.