Analytical measurements of certain heavy metals implicated developmental disorders are important in order to prevent and diagnose exposure. While the experimental conditions of many electrochemical methods have been optimized for large sample volumes using conventional macroelectrodes, this work addresses the challenges associated with scaling down the analysis to smaller volumes and replacing large electrodes with microelectrodes. While the bulk analyte concentration is not expected to change dramatically during conventional voltammetry analyses, we measured a significant depletion of metal ions when milliliter volumes were used. We showed that ion depletion from a solution of small enough volume and low enough concentration was possible, and from preliminary tests the optimum deposition step for a Pb<sup>2+</sup> ion was around 400 seconds for the electrode and cell geometry that we were using. In addition, we have explored the use extraction techniques that can be readily scaled down to small volumes. Preliminary results suggest that when iodide is used to form a neutral complex with several heavy metals, including cadmium, this complex can be effectively extracted into a nonpolar phase. Unlike many other extraction methods which are often incompatible with voltammetry, we hope to show that this particular extraction technique does not interfere with our ability to pre-concentrate heavy metals on a small electrode.

Optimization of the voltammetric analysis of heavy metals

249th National Meeting (2015)

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