Sensitive SERS detection and characterization of procaine in aqueous media by reduced gold nanoparticles

•Sensing of procaine was investigated using SERS with Au nanoparticles.•The assignment of vibrational modes was performed by density functional theory.•SERS establishes a wider linear dynamic range and better detection limits over reported methods.•Modes prediction of interactions between procaine and gold resulting in signal enhancement. Surface-enhanced Raman scattering (SERS) spectroscopic technique was implemented for the determination of procaine in aqueous media by utilizing gold nanoparticle as substrates. A reduction technique was used to prepare the gold nanoparticles which were characterized by infrared and Raman methods. SERS spectra of procaine were recorded at a wide range of concentrations, and the Raman peaks along with their spectroscopic shifts have been identified and assigned. A Density Function Theory (DFT) calculation method was developed to understand possible interaction modes between gold atoms and procaine molecules. The intensity enhancement obtained for a number of Raman peaks were employed to develop a reliable quantitative determination approach for procaine in aqueous solutions. Such an approach exhibited high sensitivity and reproducibility with a reasonably wide linear dynamic range. The limit of detection of procaine achieved was up to 1 × 10–10 M, which is considered competitive compared to other previously reported analytical methods.