A novel gold nanosol SERS quantitative analysis method for trace Na+ based on carbon dot catalysis

The Ca-doped carbon dots (CDca) exhibited strong catalysis of HAuCl4-H2O2 reaction to produce gold nanoparticle (AuNP), using Vitoria blue 4R (VB4r) as molecular probe, it appeared a strong surface enhanced Raman scattering (SERS) peak at 1615 cm(-1) in the AuNP nanosol substrate. When catalyst CDca increased, the SEAS peak enhanced linearly owing to AuNPs increasing, that is, the AuNP concentration is linear to SEAS signal. Potassium pyroantimonate (PA) ligand can adsorb on CDca surface to inhibit the catalysis and cause the SEAS peak decreasing. The analyte of Na+ reacts with PA to produce the stable precipitate of [Na-2(PA)] and free CDca catalyst. The more Na+, the more CDca released, and the stronger SEAS signal due to more AuNP substrate. Accordingly, a SEAS quantitative analysis method for Na+ was developed based on CDca catalytic SEAS reaction, with a linear range of 0.004-0.043 mu mol/L, and a detection limit of 0.0019 mu mol/L Na.