A new Fe/N doped carbon dot naocatalytic amplification-aptamer SERS/RRS/Abs trimode assay platform for ultratrace Pb²

Nanocatalytic amplification of carbon dots is a new way to improve sensitivity. The preparation of the high catalytic activity and stable iron/nitrogen-doped carbon dot (CD_BFe) sol and its application in aptamer (Apt) assay have not been reported yet. In this paper, a simple hydrothermal procedure for the preparation of CD_BFe derived from Fe²⁺-2,2'-bipyridine complex has been developed. It is found that CD_BFe has a strong catalytic effect on the indicator reaction of glyoxal (C₂H₂O₂) reduction of HAuCl₄ to produce gold nanoparticle (AuNP) probe with strong surface enhanced Raman scattering (SERS) at 1617 cm^-1, resonance Rayleigh scattering (RRS) effect at 370 nm and absorption (Abs) at 550 nm. A rapid and sensitive CD_BFe catalytic amplification Apt method for SERS/RRS/Abs trimode detecting ultratrace lead ions was established, based on the Apt reaction mediated the nanocatalytic indicator reaction. The results show that the SERS intensity and Pb(II) concentration have a good linear relationship in the range of 1.3-16 pM, and the detection limit is the lowest. In addition, Hg(II) and As(III) can also be measured by this naocatalytic amplification- Apt assay platform.