Nanocrystalline boron-doped diamond nanoelectrode arrays for ultrasensitive dopamine detection

•BDD-NEAs for low-level dopamine detection without selective membrane are presented.•DA detection at O-terminated BDD shows a signal largely independent of AA.•Differential pulse voltammetry is employed to improve the DA sensitivity.•Detection limit less than 100 nM under physiological conditions is achieved.

In this paper we present nanocrystalline boron-doped diamond nanoelectrode arrays (BDD-NEAs) for the low-level detection of biogenic substances such as dopamine (DA) without the need for a selective membrane. We achieved a sensitive and reproducible detection of dopamine in the presence of ascorbic acid (AA) with oxygen (O-) terminated BDD-NEAs. To improve the peak separation between dopamine and ascorbic acid, differential pulse voltammetry (DPV) was employed. Therewith, it was possible to measure dopamine with a sensitivity of 57.9 nA μM−1 cm−2. The detection limit was less than 100 nM with a linear behavior up to a concentration of 20 μM. The choice of the appropriate termination, the combination of the advantages of nanoelectrode arrays together with the outstanding electrochemical properties of boron-doped diamond and the right measurement method allowed successful measurement of dopamine in physiological concentrations in the presence of ascorbic acid.

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