Fabrication of an Electrochemical Sensor for Determination of Epinephrine Using a Glassy Carbon Electrode Modified with Catechol

The electrochemical behavior of epinephrine (EP) at the catechol modified glassy carbon electrode (catechol/GCE) in phosphate buffer solution (PBS, pH = 7.0) was examined using cyclic voltammetry (CV), chronoamperometry (CA) and differential pulse voltammetry (DPV). The results of electrochemical studies confirmed the ability of catechol to accelerate the electron transfer process and reduce overvoltage for the oxidation of EP. DPV studies showed two dynamic ranges, of which in the low concentration range of EP, the detection limit was reported to be 1.6 µM. Moreover, the reproducibility, repeatability and selectivity of the designed sensor were investigated using DPV method. The selectivity of this sensor was studied in the presence of interfering substances such as glucose, fructose, ascorbic acid, sodium chloride, potassium chloride, norepinephrine and dopamine. Catechol/GCE was used for quantitative measurements of EP in human blood serum sample. DPV studies reported two linear segments with slopes of 0.0186 and 0.0068 µA µM-1 in the concentration ranges of 5.0-80.0 and 100.0-900.0 µM, respectively. The detection limit (3Sb/m) and sensitivity for the low concentration range of EP were found to be 1.61 µM and 0.6 µA µM-1 cm-2, respectively.