Ultrasensitive and Highly Selective Electrochemical Detection of Dopamine Using Poly(ionic liquids)–Cobalt Polyoxometalate/CNT Composite

A novel sandwich polyoxometalate (POM) Na12[WCo3(H2O)2(CoW9O34)2] and poly(vinylimidazolium) cation [PVIM+] in combination with nitrogen-doped carbon nanotubes (NCNTs) was developed for a highly selective and ultrasensitive detection of dopamine. Conductively efficient heterogenization of Co5POM catalyst by PVIM over NCNTs provides the synergy between PVIM–POM catalyst and NCNTs as a conductive support which enhances the electron transport at the electrode/electrolyte interface and eliminates the interference of ascorbic acid (AA) at physiological pH (7.4). The novel PVIM–Co5POM/NCNT composite demonstrates a superior selectivity and sensitivity with a lowest detection limit of 500 pM (0.0005 μM) and a wide linear detection range of 0.0005–600 μM even in the presence of higher concentration of AA (500 μM).