Electrochemical determination of 2-isopropoxyphenol in glassy carbon and molecularly imprinted poly-pyrrole electrodes

A simple, rapid and sensitive electrochemical method using a molecularly imprinted polymer (MIP) based on the electropolymerisation of pyrrole (Py) was developed for the determination of 2-isopropoxyphenol (IPP) in model and real samples. The electrochemical behavior of IPP was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) on bare glassy carbon (GC) electrodes in a Britton-Robinson buffer (pH, 2) solution. IPP exhibited a quasi-reversible behavior on a GC electrode. An anodic peak for IPP showed good linearity over a concentration range from 0.21 to 75 μM (r2 = 0.999) with a limit of detection (LOD) of 0.21 μM in DPV. For the theoretical design of the MIP, to screen suitable functional monomers and to optimize monomer-template mole ratio, a computational approach was followed using density functional (B3LYP) and Semi-Empirical Parameterized Model number 3 (PM3) models. Pyrrole monomers in the presence of IPP template were electrochemically polymerized using CV on the working electrode. The sensor exhibited an oxidation peak at 0.737 V and an excellent linearity (r2 = 0.9969) toward increasing concentration of the template over the range 0.09-45 μM with a LOD of 0.09 μM. Intra- and inter-day assay precisions, expressed as %RSD, were overall less than 8.67% for both methods. The result of the selectivity experiment showed that the imprinted sensor has a good response and selectivity toward IPP. The developed sensors were successfully applied for the determination of IPP in real samples recovered from in vitro metabolism of Propoxur (PPX).