The high mass transport caused by ultrasonic radiation in the preconcentration of trace metal species in anodic stripping voltammetry (ASV), leads to an order of magnitude enhancement in sensitivity. A Nafion-coated mercury thin-film working electrode is placed in a specially designed small-volume sonovoltammetric cell. The preparation and curing procedure for the Nafion film on a glassy carbon electrode substrate as well as ultrasound-enhanced mercury deposition through the Nafion film are optimized. The resulting electrode assembly is stable under ultrasonic irradiation. Optical microscopy observations show the formation of closely spaced mercury droplets of micrometer dimensions under the Nafion film. The performance characteristics of ultrasound-enhanced ASV at the Nafion-coated mercury thin-film electrode are studied in detail. The detection limit obtained for lead and cadmium test species is 3 × 10 -11 M (30 s preconcentration in the presence of ultrasound). A relative standard deviation of 1.2% is obtained for repetitive determinations of 10 nM Cd 2+ (n ) 9).Anodic stripping voltammetry (ASV) is well established as a powerful method for trace metal analysis. 1 Its inherent sensitivity results from preconcentrating the metal of interest into or onto an electrode followed by an anodic stripping step, usually using a differential pulse or square wave voltammetric scan.Potentially, the detection limit can be lowered via more efficient preconcentration. In other words, the higher the rate of mass transport during the deposition period the lower the attainable limit of detection. However, other prerequisites such as reproducibility of mass transport and stability of the electrode assembly under the preconcentration conditions have to be fulfilled. Several effective strategies have been described for preconcentrating the analyte in stripping voltammetric determinations. These include hydrodynamic systems such as the rotating disk electrode 2,3 and stationary electrodes in combination with flowing solutions, typically in wall-jet 4-6 configurations. Frequently, stirring is also used to impose convection in the electrolyte solution. In the case of microelectrodes, it has been demonstrated that sufficiently effective preconcentration can be achieved in quiescent solution on the basis of (hemi)spherical diffusion. 7,8 Sonovoltammetry, i.e., the performance of voltammetry in the presence of ultrasound, has recently been established as a powerful tool for studying electrochemical processes. 9-14 The attractive features of ultrasound-enhanced voltammetry are as follows: (i) Ultrasonic irradiation leads to very high mass transport of electroactive species and their products to and from the electrode surface. 10,14 (ii) Ultrasound can influence the mechanism of chemical and electrochemical reactions via the action of highly reactive radicals such as • OH and • H formed during sonolysis of water. 15,16 (iii) The adsorption of species involved in an electrochemical reaction can be reduced in the presence of ultrasound....