A novel nickel nanowire amperometric sensor: Direct current vs. alternating current strategies for ethanol, acetaldehyde and acetylcholine detection

• A nickel nanowire array sensor was used to evaluate ethanol, acetaldehyde and Ach.
• Direct current evaluation and a novel alternating current strategy were compared.
• The dependence of the current fluctuations with the evaluated compounds were confirmed.

The electrochemical detection of ethanol, acetaldehyde and acetylcholine using a nickel nanowire array electrode was studied. For each compound, the sensitivities, detection limits and coefficients of determination obtained by the traditional direct current (DC) amperometric technique using the nanowire array electrode were compared with the results obtained using a flat electrode, and for the three compounds the nanowire array electrode showed improved performance. The amperometric responses displayed current fluctuations with root mean square amplitudes linearly related to the concentration of each compound in solution, and from their analysis the alternating current (AC) sensitivities and coefficients of determination of the three compounds were determined. Although the AC responses were less sensitive than the corresponding DC responses, the AC strategy allows determining the concentration of the compounds without requiring the independent measurement of the background currents flowing through the electrode in the absence of the compounds under analysis.