Quantitative analysis model based on surface-enhanced Raman spectroscopy of malachite green adsorbed on gold nanoparticles film substrates

Abstract

In order to investigate the adsorption process of malachite green (MG) on gold nanoparticles, a simple gold nanoparticles-assembled film was prepared as a substrate of surface-enhanced Raman spectroscopy (SERS), and it was soaked in MG solutions of different concentrations. The kinetic adsorption process was investigated by SERS method and density functional theoretical calculations. When saturated adsorption was achieved, the relationship between the characteristic SERS band signal intensity and the logarithm of solution concentration of MG was consistent with Temkin adsorption isotherm model, where the R² value was greater than 0.995, and the linear range was 1 × 10⁻³–1 × 10⁻⁷ M. Finally, a SERS quantitative analysis model of the relationship between the adsorption properties of surface species and the bulk concentration was established. According to the electrostatic interaction and co-adsorption, we proposed the surface adsorption configurations and adsorption process of MG on the nanostructured gold films.