Patent blue v, one of synthetic colours, is commonly used to improve the appearance of foods in Europe, but the health concerns associated with synthetic colours has been sometimes reported. In present study, a sensitive and simple analytical method for patent blue v in drinks was established by surface enhanced Raman scattering (SERS). Two gold nanoparticles synthetic methods were compared and the characteristic peaks for patent blue v were certified by density functional theory. The results showed that the intensity of 1,182 cm^-1 semi-quantitative peak was proportional to the concentration of patent blue v. The detection limit concentrations were among 0.5 to 1.0 mg/kg in different drinks. The relative standard deviations were below 7.75%, and the average recovery rate was in the range from 92.09% to 104.55%. In conclusion, the application of SERS method has a promising prospect in drinks to detect patent blue v because of its simplicity and efficiency.

Graphical abstract - Detection of virgin olive oil adulteration by rheology.