Abstract

A glassy carbon electrode (GCE) modified with valine was used for the sensitive volt metric determination of
epinephrine (EP). The electrochemical response characteristics of the modified electrode toward EP, ascorbic acid (AA)
and dopamine (DA) were investigated by cyclic voltammetry (CV). The results show an efficient catalytic activity of
the electrode for the electro-oxidation of EP, which leads to an improvement to the reversibility of the electrode
response. The effect of pH and potential sweep rate on the mechanism of the electrode process was investigated. The
modified electrode exhibits an efficient electron mediating behavior along with well-separated oxidation peaks for EP,
AA, and DA. Under the optimum pH of 7.0 in phosphate buffer solution(PBS), the CV anodic peak current showed a
linear relation versus EP concentration in the range of 4.5×10-6~1.0×10-5mol·L-1 and 1.0×10-5~1.4×10-4 mol·L-1, with
correlation coefficients of 0.9997 and 0.9942. The detection limit is 7.6×10-7 mol·L-1. High sensitivity and selectivity,
submicromolar detection limit, high reproducibility, along with ease of preparation and regeneration of the electrode
surface by simple polishing make this method suitable for the determination of EP in pharmaceutical and clinical
preparations.

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