Molecularly imprinted conducting polymer for determination of a condensed lignin marker

Condensed lignin is an undesired byproduct that has detrimental effects in cellulose pulping processes, increasing the consumption of bleaching chemicals and altering the properties of main products. A simple method for quantification of condensed lignin could greatly improve the performance and economy of pulping mills. In this work, a chemical sensing material based on a molecularly imprinted conducting polymer was synthesized by using a marker of condensed lignin as template molecule. Molecular modeling was used as an essential tool to understand and optimize the complexation of the functional monomers with the template in order to improve the synthesis strategy. The imprinted polymer was synthesized by co-electropolymerization of 3,4-ethylenedioxythiophene (EDOT) and 3-acetic acid thiophene (AAT) in presence of 2,2’-methylenebis(2-methoxy-4-methylphenol) as template, and studied by cyclic voltammetry and electrochemical impedance spectroscopy. The anodic peak current at +0.88 V (vs. Ag/AgCl/KCl 3 M) in the cyclic voltammograms of the imprinted polymer sensor was used to detect the lignin marker dissolved in pure solvents at concentrations ranging from 1 × 10−6 to 1 × 10−2 M.