Electrochemiluminescent determination of methamphetamine based on tris(2,2′-bipyridine)ruthenium(II) ion-association in organically modified silicate films

Tetramethoxysilane (TMOS) and dimethyldimethoxysilane (DiMe-DiMOS) were used as co-precursor to immobilize poly(p-styrenesulfonate) (PSS), then tris(2,2′-bipyridine)ruthenium(II) (Ru(bpy)32+) was successfully immobilized on a glass carbon electrode via ion-association. The immobilized Ru(bpy)32+ shows good electrochemical and photochemical activities. Electrochemical and electrochemiluminescence (ECL) characterizations of the organically modified silicates (ORMOSILs) modified film electrodes were made by means of cyclic voltammetry and chronocoulometry. The ORMOSIL films were investigated by atomic force microscopy, scanning electrochemical microscope, tunnelling electrochemical microscope, X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and fluorescence spectroscopy. XPS in-depth profiles revealed a homogeneous distribution of Ru(bpy)32+ inside the silica thin layers. The modified electrode was used for the ECL determination of methamphetamine (METH) and showed high sensitivity. Detection limit was 2.0 × 10−7 mol l−1 for METH (S/N = 3) with a linear range from 5.0 × 10−7 to 1.0 × 10−3 mol l−1 (R = 0.986). The relative standard deviation (n = 6) was 1.1% for the determination of 1.0 × 10−5 mol l−1 METH. Furthermore, the Ru(bpy)32+ immobilized modified electrode was applied in the ECL determination of methamphetamine (METH) in scout cases.