Electrogenerated chemiluminescence sensor for metoclopramide determination based on Ru(bpy)32+-doped silica nanoparticles dispersed in Nafion on glassy carbon electrode

A novel method for the determination of metoclopramide (MCP) using electrogenerated chemiluminescence (ECL) is presented. A tris(2,2'-bipyridyl)dichlororuthenium(II) (Ru(bpy)(3)(2+))-doped silica (RuDS) nanoparticle/perfluoinated ion-exchange resin (Nafion) with nanocomposite membrane modified glassy carbon electrode (GCE) is used. The Ru(bpy)(3)(2+) encapsulation interior of the silica nanoparticle maintains its electrochemical activities and also reduces Ru(bpy)(3)(2+) leaching from the silica matrix when immersed in water due to the electrostatic interaction. The analytical performance of this ECL sensor for MCP is shown in detail. Under optimal experimental conditions, it has good linearity in the concentration range from 2 x 10(-8) mol/L to 1 x 10(-5) mol/L (R= 0.9989) with a detection limit of 7 x 10(-9) mol/L. The relative standard deviation (n = 11) is 3.2% for detecting 1.2 x 10(-6) mol/L MCP. The recoveries are in the range of 97.0-104.4% for sample measurements by standard-addition method. This method has been applied successfully to determine MCP in pharmaceutical preparations and in human urine. Statistical analysis (Student's t-test and variance ratio F-test) of the obtained results show no significant difference between this proposed method and the reference method. (C) 2008 Elsevier B.V. All rights reserved.