User:Sarah Haack/Notebook/Capstone Research/2012/02/22
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Cyclic Voltammetry: Setting Up The Experiment
Next week's research will begin a look into the electrochemical properties of the various metallic protoporphyrins via cyclic voltammetry, a technique that measures that the electrochemical properties of a compound. The end result of cyclic voltammetry is twofold: one set of data, resembling peaks, measures the cathodic potential of a substance against time, reaching a peak at the maximum reduction potential. The second, resembling more of a parabola than a peak, measures the current at the working electrode against the applied, or potential voltage.
This lab's experiment will involve the same protoporphyrin IX substances as used in previous experiments: iron, nickel, cobalt, copper, and manganese. The PP IX samples will be made into a 10^-3 M solution with the solvent acetonitrite, a common solvent for cyclic voltammetry experiments. An electrolyte of 0.1 M sodium borate will be added in order to bolster the current and continue the electric charge between the electrodes. The working electrode will be glassy carbon, the reference electrode will be silver, and the counter electrode will be platinum. The system will be run starting 0.1 V, with scans running 20 mV/s for 10 minutes each. The system will be powered by a potentiostat, which provides current without changing the voltage. Between each trace, the electrodes will be rinsed so that the analytes, with changed charge, do not disrupt the charge. The solution should also be stirred between traces, but not during, in order to provide fresh analyte to the surface of the electrodes.