Silver nanosol SERS/Flu/Abs trimode analysis of trace H2O2 based on Fe-doped carbon dot catalytic oxidation of TMB

Abstract

A stable Fe-doped carbon dot (CDFe) nanosol with high catalytic activity was prepared by water hydrothermal procedure using ferrocene as precursor. In Tris-HCl buffer solution, 3,3′,5,5′-tetramethylbenzidine (TMB) was oxidized slowly by H2O2 that catalyzed quickly by CDFe. The oxidation product (TMBox) molecular probes exhibit surface-enhanced Raman scattering (SERS) peak at 1606 cm−1 in the silver nanosol substrate, fluorescence (Flu) peak at 400 nm and absorption (Abs) peak at 560 nm. With the increase of H2O2 concentration, the produced TMBox increased, and the SERS/Flu/Abs peaks were enhanced linearly. Based on this, a new SERS/Flu/Abs trimode molecular spectral method was established for the determination of trace H2O2 based on CDFe catalytic amplification. The results show that the SERS linear range for H2O2 concentration is 5.0 × 10−10–2.5 × 10−8 mol/L, and the detection limit is 2.52 × 10−10 mol/L. The H2O2 contents in food samples were analyzed by this SERS quantitative method, with relative standard deviations of 2.1–4.3 % and recovery of 94.5−103.8 %.