One‐Step Synthesis of Ru(2,2′‐Bipyridine)3Cl2‐Immobilized Silica Nanoparticles for Use in Electrogenerated Chemiluminescence Detection

Abstract One‐step synthesis of Ru(bpy) 3 Cl 2 ‐immobilized (bpy = 2,2′‐bipyridine) silica nanoparticles (Ru–silica nanoparticles) for use in electrogenerated‐chemiluminescence (ECL) detection is reported. Ru–silica nanoparticles are prepared by using the Stöber method. Compared with free Ru(bpy) 3 Cl 2 , Ru–silica nanoparticles are seen to exhibit a red‐shift of the UV‐vis absorbance peak and a longer fluorescence lifetime, which are attributed to the electrostatic interaction of Ru(bpy) 3 2+ and silica. Because silica nanoparticles are used as immobilization matrices, the surfaces of Ru–silica nanoparticles are easily modified or functionalized via the assembly of other nanoparticles, such as Au. For ECL detection, Au‐colloid‐modified Ru–silica nanoparticles are immobilized on a 3‐mercaptopropyl‐trimethoxysilane‐modified indium tin oxide electrode surface by Au–S interaction; the surface concentration of electroactive Ru(bpy) 3 Cl 2 is obviously higher than that in silica films. The modified electrode exhibits excellent ECL signals and gives a good linear range over 5 × 10 –7 –1.4 × 10 –3 M with a detection limit of 50 n M towards the tripropylamine (TPA) detection. Moreover, the electrode has better reproducibility and long‐term stability for the determination of TPA than electrodes modified with pure Nafion, Nafion–silica, Nafion–TiO 2 , or sol‐gel films containing Ru(bpy) 3 Cl 2 . Immobilization of Ru(bpy) 3 Cl 2 on the electrode surface by this method is simple and easy, so it shows potential applications in the field of ECL analysis and detection.