We report an innovative and environmentally friendly technique that integrates column chromatography with surface-enhanced Raman scattering (SERS). It works in concert to meet the demand for an economical and intuitive method for color analysis and detecting illegal applications of colorants in food. Alumina powder was modified sequentially to provide dual functions. It is made lipophilic to serve as the stationary phase for reversed-phase liquid chromatography. It is also impregnated with silver nanoparticles (AgNPs) to be a native SERS sensor. This column technology is termed Visualization-Augmented Deconvolutional SERS (VAD-SERS) because it enables the separation and in situ, color-guided SERS detection of individual colorants in a composite color. The effectiveness of VAD-SERS is demonstrated in an experiment that mimics food color adulteration. It is also exhibited in the deconvolution of the color formation in commercial green and brown candies. VAD-SERS is a highly competitive analytical technique, being cost-effective, as efficient as HPLC, easy to set up and operate, and amenable to expansion to preparative scale and the analysis of colorless substances using Raman mapping.
