Simple Raman Spectroscopic System Coupled with Ag Nanostar Colloid as SERS Substrate for Detection of Low Concentrations of Water Pollutants

Abstract

Raman spectroscopy is considered an effective characterization tool for the quantitative detection of pollutants in water, especially when coupled with surface enhanced Raman scattering ‎‎(SERS) technique. SERS is a highly sensitive and selective approach; it improves Raman signals by using nano-materials as substrates. ‎In this study, a low-cost Raman detection system was designed, ‎manufactured, and integrated with SERS technique using a star-shaped nanosilver ‎‎(AgNS) colloidal solution as a ‎liquid substrate to enhance Raman detection at low ‎concentrations of pollutants. The AgNS colloid was synthesized from ‎silver ions using ‎a chemical reduction method. ‎Sodium nitrate solutions with various concentrations ‎were used as water pollutants. Using SERS technique, the ‎results showed a noticeable improvement in the ‎Raman signal of the sodium nitrates' ‎spectra samples. ‎The ‎highest analytical enhancement factor for SERS was 7.48 for ‎the sample of the ‎lowest concentration (0.05M) of sodium nitrates.‎