Reducing the detection limit of trace metals in water by electrodeposition-assisted laser-induced breakdown spectroscopy with gold nanoparticles

Abstract

This paper used gold nanoparticles to improve the detection limit of laser-induced breakdown spectroscopy (LIBS) for detecting trace metals in water. Firstly, the Pb and Cr elements in water were enriched to the surface of the Al metal substrate by electrodeposition, the substrate surface with Pb and Cr was dripped with Au NPs solution of different concentrations, then dried, and finally, LIBS analysis was carried out. The results showed that the emissions of Pb (I) and Cr (I) rose and then dropped with the Au NPs concentration, reaching the maximum emission intensity when the concentration of Au nanoparticles was 3.91 ng/mL. Secondly, this paper constructed the standard curves of Pb and Cr in the water, and calculated the limit of detection (LOD), finding that the LOD of Pb and Cr at the Au NPs concentrations of 3.91 ng/mL were lower than those without the Au NPs (0 ng/mL). LOD was reduced to less than half of that without gold nanoparticles. The results showed that, compared with electrodeposited LIBS, nanoparticle-enhanced electrodeposited LIBS could realize the high-sensitivity analysis of heavy metals in the water.