SERS-based Au@Ag core-shell nanoprobe aggregates for rapid and facile detection of lead ions

The public is seriously at risk for major health problems due to environment contamination from lead ions (Pb 2+ ) and heavy metal bioaccumulation in agricultural goods. In this study, core-shell silver-coated gold nanorods (Au@Ag NRs) were created and treated with glutathione (GSH) and 4-aminobenzoic acid (4-MBA) to monitor Pb 2+ using the surface-enhanced Raman scattering (SERS) technique. Its free carboxyl groups can chelate Pb 2+ added in solution and then present self-aggregated, bringing about more “hot spots” to acquire the significant enhancement signal of 4-MBA. The SERS intensity had a good linear correlation (y = 2420.81x+11333.62, R 2  = 0.9914) in the dynamic range of Pb 2+ concentration of 0.5–1000 μg/L under the current optimization conditions, and LOD was 0.021 μg/L. In addition, recoveries of 94.17–101.12% and 81.31–97.86% for Pb 2+ in tea powder and glutinous rice flour confirmed the monitoring accuracy of Pb 2+ , highlighting its huge potential in the monitoring food quality and safety.