Cyclic and pulse voltammetric study of dopamine at the interfacebetween two immiscible electrolyte solutions

• The detection of dopamine by differential pulse voltammetry (DPV) and square wave voltammetry (SWV) at the interface between twoimmiscible electrolyte solutions (ITIES) has been studied. Voltammetry at the liquid/liquid (water/1,2-dichloroethane) interface provides asimple method for overcoming the major problem associated with dopamine detection by voltammetry at solid electrodes: the co-existenceof ascorbate at higher concentrations. Selectivity for dopamine was achieved by the use of dibenzo-18-crown-6 as an ionophore for thefacilitated transfer voltammetry of protonated dopamine across the ITIES. Under these conditions, ascorbate is not transferred and hence doesnot interfere in the ion transfer current for dopamine. By use of DPV and SWV, the lowest concentration detectable can be lowered from ca.0.1mM (obtained with cyclic voltammetry) to 2 M. Evaluation of the effect of some other physiologically important species (acetylcholine,sodium, potassium and ammonium ions) on the dopamine transfer voltammetry has been studied, indicating the need for improved ionophoredesigns in order to achieve practically useful selectivity.

Ämnesord

NATURVETENSKAP  -- Kemi -- Analytisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Analytical Chemistry (hsv//eng)

Nyckelord

Dopamine; Ascorbate; Differential pulse voltammetry; Square wave voltammetry; Selectivity; ITIES

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