Application of multi-walled carbon nanotubes modified carbon ionic liquid electrode for electrocatalytic oxidation of dopamine

A simple, sensitive, and reliable method based on a multi-walled carbon nanotubes (MWNTs) modified carbon ionic liquid electrode (CILE) has been successfully developed for determination of dopamine (DA) in the presence of ascorbic acid (AA). The acid-treated MWNTs with carboxylic acid functional groups could promote the electron-transfer reaction of DA and inhibit the voltammetric response of AA. Due to the good performance of the ionic liquid, the electrochemical response of DA on the MWNTs/CILE was better than that of other MWNTs modified electrodes. Under the optimum conditions a linear calibration plot was obtained in the range 5.0 × 10−8 to 2.0 × 10−4 mol L−1 and the detection limit was 1.0 × 10−8 mol L−1.

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► DA, AA and UA can be well separated at the CILE, and cannot interfere with each other.
► The acid-treated MWNTs are chosen for modifying the CILE.
► The modifier MWNTs offer improved voltammetric response and selectivity towards DA.
► Square-wave voltammetry is used for DA determination.