Selective Voltammetric Measurements of Epinephrine and Norepinephrine in Presence of Common Interferences Using Cyclic Square‐voltammetry at Unmodified Carbon Electrodes

Selective electrochemical measurements of epinephrine (EP) and norepinephrine (NE) in the presence of large excess of the common interfering ascorbic acid (AA) and uric acid (UA) are accomplished using cyclic square‐wave voltammetry (C‐SWV) at unmodified carbon electrodes. Such use of bare carbon electrodes is based on monitoring the reduction peaks of the EP and NE oxidation products and relies on the reversible electrochemical behavior of these catecholamines compared to that of AA and UA and on the rich information content and high speed and sensitivity of C‐SWV. Detection limits of 3 μM EP and NE are estimated in the presence of 100 fold excess AA and UA. The C‐SWV operation at the uncoated carbon electrode facilitates also the simultaneous measurements of EP and NE. The new C‐SWV protocol enhances the resolving power of unmodified carbon electrodes and represents an extremely useful and simple addition to the arsenal of electrochemical techniques for real‐time monitoring of dynamic brain processes.