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

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.