High -Sensitive Detection of Malachite Green Based on Surface-Enhanced Electrochemiluminescence

This article introduces a novel unlabeled surface-enhanced electrochemiluminescence (SEECL) sensor for malachite green (MG) detection. The SEECL sensor was prepared by modifying the Ru(bpy)₃²⁺ doped gold-SiO₂ core–shell nanocomposites (Au@SiO₂-Ru(bpy)₃²⁺) on the gold electrode. Ru(bpy)₃²⁺ of nanocomposites can not only emit electrochemiluminescence (ECL) with electrochemical reaction, but also induce the local surface plasmon resonance (LSPR) of gold core. That is beneficial to enhance the ECL signa of sensor. However, in the existence of MG, the luminescence of sensor would be quenched by the fluorescence resonance energy transfer (FRET) between MG and Ru(bpy)₃²⁺. In this paper, both fluorescence and ECL of the Au@SiO₂-Ru(bpy)₃²⁺ were investigated for MG detection. And the results show that the SEECL sensor has high sensitive to MG. Under the optimal experimental conditions, the minimum detection concentration could be achieved about 1.0 nM of MG, which fully meets the China national standard detection requirements of veterinary drug residue in seafood.