Electrochemical sensing of anions and heparin by an alkyl-chain ferrocene cationic surfactant.

Alkyl-chain ferrocene cationic surfactants (ACFcCS) can form ion-pair complexes with anions, and are then adsorbed at hydrophobic electrode surfaces or extracted to organic layers. The amount of adsorbed ACFcCS-anion complex is dependent on the anion concentration in a solution, and the anion concentration can be determined from the current intensity of the oxidation wave of the ferrocene part of ACFcCS. In this work, we studied the adsorption behavior of (ferrocenylmethyl)dodecyldimethyl ammonium ion (FcMDDMA) on a carbon-paste electrode, which accompanies the ion-pair formation with an inorganic anion, an organic anion, or heparin molecule. A concentration analysis of a heparin sodium injection sample was carried out using adsorption voltammetry, and the amperometric titration used FcMDDMA as the end-point indicator.