Researchers have developed a device that detects low concentrations of methanol in alcoholic beverages.

Swiss experts have created and tested a portable device paired with a smartphone app that can measure methanol levels. When placed over an open container, the device uses a sensor that absorbs a vapor or gas sample from the beverage, and will warn if the methanol level is potentially harmful. It processes the methanol and ethanol at different speeds, allowing the chemicals to be detected in succession.

As the technology is inexpensive, it is suitable for poorer regions wher food safety is a concern.

Scientists at the Particle Technology Laboratory (ETH) in Zurich, Switzerland spiked 89 alcoholic drinks with known levels of methanol. They found the device detected methanol accurately for 107 days of consecutive use, according to the study published in the journal Nature Food.

From 2017 to 2019, there were 306 registered methanol poisoning outbreaks, affecting 7,104 people and causing 1,888 fatalities. Ninety percent of the outbreaks were in Asia. The chemical can be formed naturally during fermentation but drinks are often deliberately adulterated with cheap methanol at up to 50 percent volume to increase profit and potency. Methanol can also accumulate in alcoholic drinks through improper brewing or distilling. It becomes highly toxic when metabolized by the human body.

Scale of the problem
In 2019, Israel’s Ministry of Health said at least 13 people had died in the country since 2018 because of methanol poisoning from alcohol. Also in 2019, Costa Rican health officials reported 76 patients had been hospitalized due to methanol poisoning and 29 had died. A total of 66,000 containers of banned beverages were seized.

In the last half of 2019, 40 cases were reported in Colombia while 33 have been recorded this year which could be associated with quarantine measures due to the coronavirus pandemic, according to the National University of Colombia.

In May this year, Mexican authorities issued a warning after the death of almost 50 people in different states due to consumption of allegedly adulterated alcoholic beverages. More than 110 people were affected in Jalisco, a Mexican state. The State Council against Addictions (CECA) said there had been around 190 deaths recently in different states due to adulterated beverages. It also estimated that between 40 to 50 percent of bottled alcohol sold in the country was tainted.

In June, officials in the Dominican Republic revealed more than 200 deaths and nearly 350 intoxications due to methanol adulterated beverages called “Clerén.”

It is believed that 500 patients have died and 60 people developed complete blindness due to methanol poisoning in Iran.

A July report in Alcohol and Alcoholism said fake news about the efficacy of substances to treat or prevent COVID-19 spread across social media. Production, distribution, and drinking alcoholic beverages are prohibited in the country.

“It was even recommended that ‘gurgling or drinking alcoholic beverages would disinfect the mouth or inside the body and prevent the infection by killing the viruses’. These factors altogether have led to numerous methanol poisoning deaths,” according to officials.

Finding methanol in beverages
Chemical methods have been needed to detect methanol but they are expensive, slow and only suitable for the laboratory. Compact gas sensors only work with a low alcohol content and cannot distinguish methanol from harmless ethanol. Currently, liquid chromatography is used for methanol testing, this is a lab technique that separates and measures different types of chemicals within a mixture. However, it is time-consuming and expensive.

In September 2019, ETH Zurich researchers presented the new technology which finds methanol and ethanol vapors within two minutes.

“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,” said Dr. Andreas Güntner.

The device weighs only 94 grams and is powered by a battery. Results are sent to a 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 be compatible with older devices.

It can be used by consumers and manufacturers to determine methanol content of alcoholic beverages. The design could be applied to other food contaminants such as to detect ammonia in spoiled fish.

The alcohol sensor uses nanoparticles of tin oxide doped with palladium. The two types of alcohol are 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 tube faster than ethanol due to its weaker adsorption onto the polymer surface.

A patent application has been submitted that covers the concept of selective methanol detection and is pending.