Ultra-sensitive non-aggregation colorimetric sensor for detection of iron based on the signal amplification effect of Fe3+ catalyzing H2O2 oxidize gold nanorods

AuNRs have two plasmon absorption bands located at 716 nm for LPAB and at 520 nm for TPAB, respectively. The blue shift of LPAB is observed in H2O2-HCl system. When Fe3+ was added to the AuNRs-H2O2-HCl system, causing the Δλ of the LPAB increased dramatically, the corresponding absorbance of the LPAB decreased and the color of the solution changed obviously, showing that Fe3+ has strong catalytic effect on the oxidation rection between H2O2 and AuNRs. Thus, new non-aggregation colorimetric sensor for the determination of Fe3+ has been established based on the signal amplification effect of catalyzing H2O2 oxidize gold nanorods. Schematic illustration of Fe3+ catalyzing H2O2 oxidizing AuNRs and that of H2O2 oxidizing AuNRs are compared and shown in Scheme 1.