Detection of Heavy Metals in Soil Using Au@SiO2 Nanoparticles and Surface Microstructure Combined with Laser-Induced Breakdown Spectroscopy.

The detection of heavy metals in soil is of great scientific significance for food security and human health. However, traditional detection methods are complicated, time-consuming, and labor-intensive. Herein, we developed a novel method using Au@SiO2 nanoparticles (NPs) and surface microstructure combined with laserinduced breakdown spectroscopy (Au@SiO2 NPs-SMS-LIBS) for the rapid detection of lead (Pb), chromium (Cr), and copper (Cu) in soil samples. The surface microstructures and Au@SiO2 NPs were prepared to improve detection sensitivity and stability. The limits of detection (LODs) for Pb, Cr, and Cu were 0.36 mg/kg, 0.32 mg/ kg, and 0.28 mg/kg, respectively, with relative standard deviations (RSDs) of 5.47-6.72 %. The mechanisms of spectral performance enhancement of LIBS detection were thoroughly investigated. Furthermore, the stacking combination model was developed to improve quantitative accuracy, with the correlation of the prediction set (Rp2) for Pb, Cr, and Cu being 0.9285, 0.8625, and 0.9160, respectively. This work offers a very promising solution to improve the sensitivity, stability, and accuracy of heavy metal detection. The developed method holds great application potential for large-scale soil assessments and real-time heavy metal pollution monitoring.