Synthesis and a new mercury (II) ion sensor application of conductive polymer containing rhodamine B

Abstract

An esterification reaction was carried out between Rhodamine B and 9H-carbazole-9-ethanol and then this monomer was polymerized via electropolymerization by cyclic voltammetry technique. The structure of monomer was identified by FT-IR, UV–Vis, NMR, LC-MSMS and elemental analyses. The structures of polymer and the reactants were identified by FT-IR analyses. UV–Vis spectra of the monomer and polymer were also compared. The monomer had heterocyclic structure containing nitrogen and high electron density groups. The polymer was coated on ITO/glass and screen-printed electrode (SPE) and characterized via scanning electron microscopy (SEM) measurement. The working range of the selectivity to mercury (II) ion was adjusted to the range of 10−2 M-10−9 M and 10−2 M-10−11 M for ITO/glass and screen-printed electrode system, respectively. Limit of detection (LOD) values were found to be 6.4 × 10−9 M and 2.02 × 10−12 M by ITO/glass and screen-printed electrode systems, respectively. Response times at seconds calculated for the mercury (II) concentration of the electrode was measured using open circuit potentiometer. The sensitivities of the electrodes were found to be very good. Reusability of the polymer based sensor was examined at various conditions. The unresolved problem for re-using the electrodes was overcome in this study.