Application of synchronous fluorescence scanning for authenticity identification of beer and beer-based drinks

Due to increased state control over the production and circulation of distilled spirits, alcoholic products that do not comply with mandatory licensing, primarily beer and beer beverages are increasingly being adulterated. For their quality control the application of synchronous fluorescence scanning spectroscopy is described. Four beer samples and fifteen beer beverage samples were investigated. A double-beam spectrophotometer-fluorimeter SFF-2 «Fluoran» was used for the measurements. To optimize the parameters ensuring the highest information content of the obtained spectra with minimal time expenditure, the wavelength ranges of emission and excitation, their difference (Δλ), and instrument settings were varied during the experiments. Synchronous scanning of authentic and adulterated samples was performed in the wavelength range of 250 – 600 nm at wavelength differences between excitation and emission of Δλ = 30 and 60 nm. The synchronous scanning spectra of genuine beer and beer beverages clearly exhibit high-intensity maxima in the short-wavelength region at 280 (Δλ = 30 nm) and 275 nm (Δλ = 60 nm), as well as a distinct minimum at λ = 313 nm. The long-wavelength maximum was observed at 362 (Δλ = 30 nm) and 336 nm (Δλ = 60 nm). In the adulterated samples, the position of the long-wavelength maximum remained unchanged. Analysis of the obtained data showed that some beer beverage and beer samples exhibit characteristic responses from marker fluorescent compounds present in them. Other samples either lack such responses or show significantly lower intensity. It was also demonstrated that beer samples from the same batch but sold in different regions have very similar fluorescence characteristics. This method can be used for the rapid detection of adulterated products; however, further research is needed to accumulate a statistically significant dataset.