Transition element speciation in freshwater systems, such as the Great Lakes, is dominated by organic complexation. Despite the importance of metal-organic complexation, few analytical techniques are capable of assessing speciation in environmental systems without significant kinetic limitations. To address this need we developed fast-scan deposition�stripping voltammetry (FSDSV) on carbon fiber microelectrodes for in situ measurements of transition elements with 100 ms temporal resolution. In this work, we utilize FSDSV to measure changes in copper speciation during photolysis. Experiments were designed to explore the role that aromatic moieties present within dissolved organic matter (DOM) play in controlling copper cycling in natural systems.  Our results demonstrate rapid photoredox reactions induced by UV light result in dynamic release of copper. Upon cessation of UV light, a portion of the liberated copper is recomplexed by the photo-transformed DOM. The kinetics for copper and oxygen species are quantified and chemical mechanisms are proposed.

Photochemical release of Cu from DOM complexes measured by fast-scan deposition-stripping voltammetry

245th National Meeting (2013)

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