Methanol is sometimes referred to as ethanol's deadly twin. While the latter is the intoxicating ingredient in wine, beer, and liquor, the former is a chemical that becomes highly toxic when metabolized by the human body. Even a relatively small amount of methanol can cause blindness or prove fatal if left untreated.
Cases of poisoning from the consumption of alcoholic beverages tainted with methanol occur particularly in developing and emerging countries because alcoholic fermentation also produces small quantities of methanol. Whenever alcohol is unprofessionally distilled in backyard operations, relevant amounts of methanol may end up in the liquor. Beverages that have been adulterated with windshield washer fluid or other liquids containing methanol are another potential cause of poisoning.
Until now, methanol could be distinguished from ethanol only in a chemical analysis laboratory. Even hospitals require relatively large, expensive equipment in order to diagnose methanol poisoning. This equipment is rarely available in emerging and developing countries, where outbreaks of methanol poisoning are most prevalent.
The affordable handheld device is based on a small metal oxide sensor. It is able to detect adulterated alcohol within two minutes by “sniffing out” methanol and ethanol vapors from a beverage. The tool can also be used to diagnose methanol poisoning by analyzing a patient's exhaled breath. In an emergency, this helps ensure the appropriate measures are taken without delay.
The highly sensitive alcohol sensor was developed 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.
In laboratory tests, the device detected even trace amounts of methanol contamination selectively in alcoholic beverages, down to the legal limits. Furthermore, the scientists analyzed breath samples from a person who had previously drunk rum. For test purposes, the researchers subsequently added a small quantity of methanol to the breath sample.
Methanol is being considered as a potential future fuel, since vehicles can be powered with methanol fuel cells. A further application for the new technology could be as an alarm sensor to detect leaks in tanks.