Clay modified carbon paste electrode for the voltammetric detection of dopamine in presence of ascorbic acid

α-Cobalt (II) hydroxide (α-Co-SO4) was synthesized. Characterized by powder X-ray diffraction, FT-IR spectroscopy, as well as elemental analysis indicates the formation of α-cobalt (II) hydroxide. The synthesized α-Co (II) hydroxide was used to fabricate modified carbon paste electrode for the determination of dopamine. The α-Co-SO4/SDS/CPE was characterized by electrochemical methods and modified electrode was used to determinate dopamine (DA) and ascorbic acid (AA) simultaneously. The detection limit and quantification limits for DA were found to be 2.5 × 10− 7 mol/L and 5.3 × 10− 7 mol/L respectively.

In this work, α-cobalt (II) hydroxide/SDS modified carbon paste electrode shows excellent selectivity and sensitivity toward dopamine in presence of high concentration of ascorbic acid. DA and AA usually coexist in physiological samples; the oxidation potential of AA was nearly same as that of DA results in an overlapped voltammetric response at bare CPE. The interference coming from AA can be eliminated by using α-cobalt (II) hydroxide/SDS carbon paste electrode. In the figure, curve 'a' shows mixture of DA and AA at bare and curve 'b' at modified electrode shows good electrochemical separation of DA and AA.Highlights► Anionic clay α-cobalt (II) hydroxide was synthesized by co-precipitation method. ► Biocompatible anionic clay can provide a favorable direct electrochemistry of DA. ► The modified carbon paste electrode shows excellent electrocatalytic activity. ► It shows good selectivity and sensitivity toward electrochemical detection of DA. ► The clay matrix was used to fabricate electrochemical biosensor design.