Chemosensor compound can reveal adulterated liquor

Researchers in China have identified a chemical compound that can be used to quickly identify brands and confirm the authenticity of alcoholic drinks.

The marker compound – called DHAIA – is mixed with the liquor sample, which is then measured using a fluorescence spectrophotometer and UV–vis spectrophotometer.

Slight changes in the thousand or so compounds that make up spirits and other alcoholic drinks mean that the resulting spectra differ between brands, allowing a database to be built up using the absorption and emission spectra of genuine samples. When an adulterated or counterfeit liquor is tested, the spectra differs from that in the database, flagging up the discrepancy.

According to the researchers, DHAIA is a photoluminescent intramolecular charge transfer (ICT) compound which changes its charge state depending on the chemical environment around it.

They challenged the testing procedure with a counterfeit Shede brand rice wine product that had formerly been sold on the open market and was obtained from the local police force. The authentic liquor had been replaced with an inexpensive product with the same flavour type.

"DHAIA offers the potential to be developed into a viable sensing technique for the liquor authentication to crack down on fake products, making a significant contribution to food safety, say the researchers, who have published their work in the journal Sensors and Actuators B: Chemical.

"We speculate that such [a] molecular system will bode well for fingerprinting in other complex mixtures."

They note that the technique could provide a quicker and simpler alternative to current laboratory-based tests for liquor authenticity such as chromatography, mass spectrometry, and capillary electrophoresis which are either expensive or have complicated sample preparations, and is less subjective than trained expert panellists.