Glassy carbon electrode modified with carbon black for sensitive estradiol determination by means of voltammetry and flow injection analysis with amperometric detection.

A voltammetric method for fast and sensitive estradiol determination using carbon black modified glassy carbon electrode (CBGC) is proposed. The use of carbon black as a modifying layer led to obtain low detection limit (9.2·10-8  mol L-1 for a preconcentration time of 60 s) and stability of registered signals (measured as RSD is 1.3%, n = 7, estradiol concentration 0.5·10-6  mol L-1 ). Cyclic voltammetry study revealed that in phosphate media estradiol suffers irreversible one-proton and one-electron oxidation process. Under the optimum conditions, estradiol calibration curve was linear in the concentration range from 0.15·10-6 to 3.5·10-6  mol L-1 . The proposed method enable to determine estradiol content in different pharmaceutical formulation with good recovery. Amperometric measurements of estradiol were performed as well to indicate the possibility of its fast and accurate determination under the flow conditions.