DOI: 10.22184/2227-572X.2020.10.5.410.416

Cortisol and melatonin are two hormones that directly affect wake and sleep. It is necessary to determine the content of cortisol and melatonin in body fluids to control disturbances in the sleep / wake cycles that can contribute to the development of cancerous tumors. It has been determined that gold particles deposited on a screen-­printed electrode exhibit catalytic activity during the electrooxidation of cortisol and melatonin, and the deposited particles of palladium, copper and cobalt exhibit catalytic activity only during the electrooxidation of melatonin. Dual screen-­printed electrodes modified by gold particles were used for the simultaneous two-component analysis, which allows simultaneously determine two substances at two different potentials. The linear bilogarithmic dependence of the analytical signal on the analyte concentration is observed in the ranges from 1 • 10–11 to 1 • 10–5 M for cortisol and from 5 • 10–10 to 5 • 10–3 M for melatonin. The use of a dual screen-­printed electrode modified by gold particles for the amperometric determination of cortisol and melatonin in a flow injection system provides a high throughput up to 360 samples / h.