Cyclic voltammetry and UV/Vis spectroscopy in combination with multivariate data analysis for the assessment of authenticity of poplar type propolis

Propolis, as a beneficial natural product, has found application in the food and pharmaceutical industries as a food preservative, active packaging material as well as a main component of propolis containing products. Quality control of propolis has thus gained in importance. We used simple, fast, and low-cost techniques such as UV/Vis spectrophotometry and cyclic voltammetry applied in combination with principal component analysis to confirm the presence of two botanical sub-types of propolis. Cyclic voltammetry, as a green, sensitive, and convenient technique suitable for investigation of chemical profile, together with multivariate chemometrics technique, was used for the first time for characterization and classification of propolis. UV/Vis spectroscopy was applied in two aspects, absorption at certain wavelength for the quantitative determination of analytes, i.e. determination of quality control parameters, and spectral profiles, for the confirmation of the existence of two botanically different poplar types. All investigated Serbian propolis samples were characterized with specific chemical patterns and were classified in two main botanical varieties, so-called orange and blue. The results confirmed that the applied methods have a potential to be used for the discrimination of complex natural products such as propolis.