A portable methanol detector

ETH researchers at the Department of Mechanical and Process Engineering have developed a device that detects low concentrations of methanol in alcoholic beverages. The results are displayed on a smartphone wirelessly in real time.

Smartphone App
The app visualizes the results on a smartphone. (Photo: Springer Nature)

Methanol can be lethal, even if it only occurs in small amounts. In 2019, at least 789 people who consumed alcoholic beverages contaminated with methanol died – mostly in Asia. The chemical is formed naturally when pectin is broken down during fermentation. However, the drinks are often deliberately adulterated with cheap methanol to increase profit and potency. Methanol becomes highly toxic when metabolized by the human body and at worst can be deadly.

Cheap, portable and easy to use

Until now, chemical methods were necessary to detect methanol. They are expensive, slow and only applicable in the laboratory. Compact gas sensors can be used too, but they only work with a low alcohol content and cannot distinguish methanol from the harmless ethanol. There is a need for inexpensive and reliable detectors that can be carried easily and are simple to operate.

Methanol detector
The analyzer during measurement. (Photo: Springer Nature)

In September 2019, the researchers presented the new technology (see grey box), which “sniffs out” methanol and ethanol vapors within two minutes. Now they have reached another milestone. “The main innovation is that we have turned the initial concept into a fully integrated, handheld detector, which sniffs out the smallest amounts of methanol in beverages from all continents and displays the results on a smartphone wirelessly,” says Dr. Andreas Güntner from Professor Sotiris Pratsinis’ Particle Technology Laboratory at the Institute of Energy and Process Engineering of the Department of Mechanical and Process Engineering. Whether it is wine, whiskey, rum, sake or fruit schnapps from the local traditional distillery Fassbind, the device reliably detects methanol.

The device weighs only 94 grams and measures 2x4x12 centimeters. It is powered by a battery. The results are sent to the smartphone via Wifi and displayed immediately. If no Wifi connection is available, Bluetooth can be used. The app runs on Android and iOS and should also be compatible with older devices.

One device for many purposes

The device can be used by consumers and manufacturers to determine the methanol content of alcoholic beverages. But the application does not end there. The rapid detection of methanol – perhaps even in the breath of intoxicated people – could also be useful for healthcare workers and la-enforcing authorities. The design could also be applied to other food contaminants, for example to detect ammonia in spoiled seafood. As the technology is inexpensive, it is particularly suitable for poorer regions where food safety is a concern.

Technology

The scientists developed a highly sensitive alcohol sensor using nanoparticles of tin oxide doped with palladium. Instead of analyzing the sample directly with the sensor, the two types of alcohol are first separated in an attached tube filled with a porous polymer, through which the sample air is sucked by a small pump. As its molecules are smaller, methanol passes through the polymer tube more quickly than ethanol.

References

Abegg S., Magro L, van den Broek J, Pratsinis SE, Güntner AT: A pocket-sized device enables detection of methanol adulteration in alcoholic beverages, Nature Food 2020, doi: 10.1038/s43016-020-00959

Van den Broek J, Abegg S, Pratsinis SE, Güntner AT: Highly selective detection of methanol over ethanol by a handheld gas sensor, Nature Communications 2019, doi: 10.1038/s41467-019-12223-4

More news

ETH News, 16 September 2019: Measuring ethanol’s deadly twin

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