Article ID Journal Published Year Pages File Type
1243077 Talanta 2015 8 Pages PDF
Abstract

•The as-prepared Au-Ag nanoparticles possess high intrinsic peroxidase activity.•The as-prepared Au-Ag nanoparticles act as extraordinary SERS substrates.•Trace melamine can be detected with a lower detection limit and broader linear range.

In this work, we suggest a chitosan-modified popcorn-like Au–Ag nanoparticles (CSPNPs) based assay for high sensitive detection of melamine, in which CSPNPs not only provide with an intrinsic peroxidase-like activity but also act as surface enhanced Raman scattering (SERS) substrates. CSPNPs can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 to the charge transfer complex (CTC), which contributes to a tremendous surface-enhanced resonant Raman scattering (SERRS) signals with 632.8 nm laser excitation. The target molecule melamine can generate an additional compound with H2O2, which means the available amount of H2O2 for the oxidation of TMB reduced. Correspondingly, the SERRS intensity of CTC is decreased. The decreased Raman intensity is proportional to the concentration of melamine over a wide range from 10 nM to 50 μM (R2=0.989), with a limit of detection (LOD) of 8.51 nM. Moreover, the proposed highly selective method is fully capable of rapid, separation-free detection of melamine in milk powder.

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Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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