Novel ultrasensitive and ultrafast voltammetric determination of biological aminochromes on the copper nanodoped mercury monolayer carbon fiber electrode

The influence of the biologically important aminochromes – dopaminechrome, adrenochrome, noradrenochrome and DOPAchrome – on the Cu2+/0 catalytic system by fast voltammetry (v ⩾ 200 V s−1) using a mercury monolayer carbon fiber electrode was studied. It was demonstrated for the first time that following the application of a short (0.1 ms) cathodic accumulation impulse the catalytic analytical signal of the Cu2+/0-system depends linearly on the aminochrome concentration over the range 1–200 pM. It was found that the analytical signal of the studied aminochromes was strongly amplified in the presence of thiols (reduced glutathione and cysteine) and protein (bovine serum albumin) in the analyzed solutions; while the ascorbic acid and the reduced form of aminochromes (catecholamines) did not influence this signal (the mechanism of such influence is discussed). The analytical applicability of the elaborated procedure of aminochrome quantification was confirmed by comparing the analytical signal of adrenochrome spiked with the cerebro-spinal fluid with the one of adrenochrome spiked with the bovine serum albumin.