Voltammetric detection of heparin based on anion exchange at electropolymeric film of pyrrole-alkylammonium cationic surfactant and MWCNTs composite

Electropolymeric film of pyrrole-alkylammonium (A2) cationic surfactant and multi-wall carbon nanotubes (MWCNTs) composite was firstly used to absorb Fe(CN)63 −/4 − ions as electrochemical markers to develop amperometric assay for electrochemically inactive heparin. The electrochemical behaviors of the modified platinum electrodes were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. A quite stable and well-defined redox peaks of the confined Fe(CN)63 −/4 − with negatively shifted potentials compared to the Fe(CN)63 −/4\ − in aqueous solution were observed at Fe(CN)63 −/4 −/polyA2-MWCNTs/Pt. Importantly, the ion exchange of the small anions, Fe(CN)63 −/4 − by polyanions, heparin at polyA2-MWCNTs films was observed. Thereafter, an amperometric assay for heparin based on anion exchange at Fe(CN)63 −/4 −/polyA2-MWCNTs/Pt was developed. The linear range to detect heparin with differential pulse voltammetry (DPV) is from 0.1 to 8.0 μM with the limit of detection of 0.1 μM.