Detection of Oxytetracycline in honey using SERS on silver nanoparticles

Abstract In this work, we made a review about the application of Raman spectroscopy for quality control of honey and other food samples. Simultaneously, it was carried out a new research evaluating silver nanoparticles (AgNPs) obtained by green synthesis for detection of the antibiotic Oxytetracycline (OTC), through Surface Enhanced Raman Spectroscopy (SERS). Glucose was used as reducing and capping agent in the formation of AgNPs in alkaline media. The frequencies found, belonging to the antibiotic at 20, 15, 10 and 5 ppb, could be visibly differentiated from those corresponding to honey, being unnecessary to perform any extraction procedure or tedious manipulation of the sample. Theoretical frequencies were obtained by Density Functional Theory calculations and compared with the normal modes from SERS measures, founding an excellent agreement between them. The analysis shows a preference for the adsorption of OTC on silver cluster through oxygen atoms.