This paper developed an electrochemiluminescence (ECL) method for detecting ultratrace levels of the highly toxic organic pollutant, 3,4-dichloroaniline (3,4-DCA), in water. This method has not been used previously for 3,4-DCA detection, and is based on a 96-well micro-plate modified with molecularly imprinted sal-gel films combined with multi-walled carbon nanotubes (MIF-MWCNTs). The increase in the ECL signal intensity was proportional to the 3,4-DCA concentration within a certain range, and an excellent response was obtained for 3,4-DCA concentrations ranging from 4 x 10(-11) to 6 x 10(-9) mol L-1, with a low detection limit (LOD) of 1 x 10(-11) mol L-1. The detection sensitivity of the present method is higher than those of the most commonly used chromatography methods, with the recovery of 3,4-DCA from spiked samples of water ranging from 83.3 to 110.5%. Thermodynamic analysis showed that the adsorption of 3,4-DCA by the MIF-MWCNTs occurred spontaneously as an exothermic and entropy decreasing process (Delta H = -32.49 kJ mol(-1), Delta S = -117.89 J mol(-1)). Kinetic equation fitting demonstrated that the adsorption of 3,4-DCA could be fitted by an intraparticle diffusion model, and that the adsorption isotherm data fitted the Freundlich model. (C) 2013 The Electrochemical Society. All rights reserved.