The voltammetric oxidation of testosterone (4-androsten-17β-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 0.50V 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 2.00μМ, yielding a correlation coefficient >0.99 and detection limit of 0.16μM, with relative standard deviations (R.S.D) from 1.33×10 −5 to 4.00×10 −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.
