Electrochemical detection in vitro and electron transfer mechanism of testosterone using a modified electrode with a cobalt oxide film

The voltammetric oxidation of testosterone (4-androsten-17 beta-ol-3-one) has been studied at an edge plane glassy carbon electrode modified with cobalt oxide. One sensitive and well-defined peak is obtained with a peak potential of 0.50 V vs. SCE attributed to the reduction reaction Co-IV/Co-III, which is responsible for oxidation of the steroid. A calibration curve was obtained for testosterone, with the measurements performed in triplicate, in the range from 0.33 to 2.00 mu M, yielding a correlation coefficient >0.99 and detection limit of 0.16 mu M, with relative standard deviations (R.S.D) from 1.33 x 10(-5) to 4.00 x 10(-4)% with 95% significance (p < 0.05). The modified electrode showed a stable and reproducible response toward the detection of this steroid. Thus, the results showed that the electrode modified with cobalt oxide acts as a promising alternative for simple, cheap and rapid analysis of testosterone. (C) 2014 Elsevier B.V. All rights reserved.