A hybrid technique, electrochemical ICP-atomic emission spectrometry (EC/ICP-AES), was used to study the redox-induced metal transfer from metallothionein adsorbates formed at thin mercury film (TMF) electrodes. The MT adsorbates at the TMF exhibit similar voltammetric behavior to that previously observed at dropping mercury electrodes, with peak potentials at –1.20 V, -0.75 V, and –0.32 V. During the differential pulse voltammetric (DPV) scan in the anodic direction, the Zn(Hg) and Cd(Hg) can be oxidized at –1.20 V and –0.75 V, respectively.  We suggested that the metals detected by ICP-AES originate from the reduction of the zinc-cysteine thiolates and the cadmium-cysteine thiolates during the controlled-potential MT adsorption at –1.40 V.  At –1.40 V, the TMF is negatively polarized and consequently attract the positively charged MT molecules. The electrostatic attraction should be the primary interaction between the adsorbate and the TMF because the formation of the Hg-cysteine thiolate is unlikely at such a negative potential. Interestingly, additional Zn2+ was found to co-elute with Cd2+ at –0.75 V.  We attribute the additional Zn2+ elution to the oxidation of the Cd-Zn intermetallic compound in the TMF. While Zn(Hg), the Zn-Cd intermetallic compound, and Cd(Hg) can all be completely stripped off the electrode in one DPV scan, the peak at –0.75 V, upon the initial decrease during the first DPV scan, was found to sustain through repetitive scans. This remaining peak is ascribed to the oxidation of free cysteines in the MT molecules to form the cystine (Cys-Cys) analog. We found that, the higher the MT concentration in the solution, the more the MT adsorbates will be formed. We also observed that, despite the fact that the binding affinity of MT towards Cd2+ is greater than Zn2+, a greater percentage of the initial Cd2+ in the MT molecules than that of Zn2+ had been released during the electrochemical reactions.  While the exact reason is not clear, we postulate that the extent of metal release might be related to the relative easiness in oxidizing the cysteines at different metal-binding sites with respect to the TMF surface. It is possible that certain sites are less accessible for facile electron transfer reactions. The same effect can also be used to explain the observation that, above certain MT concentrations, the electron transfer reaction between the electrode and the MT molecules in the solution phase appears to be hampered by the MT adsorbates. Consequently, metals in the solution MT molecules cannot be released or replaced. Through comparing and correlating the DPV measurements with the ICP-AES data, the on-line combination of electrochemistry and ICP-AES is demonstrated to be not only an accurate means for the determination of the metal transfer from an adsorbate film, but also as a tool that is complementary to conventional voltammetric techniques for unraveling complicated electrode reactions.