Adsorption of 4,4'-diaminodiphenyl ether on molecularly imprinted polymer and its application in an interfacial potentiometry with double poles sensor

A novel interfacial potentiometry with double poles (IPDP) sensor for detecting 4,4’-diaminodiphenyl ether (4,4’–DIADPE) has been developed by zero current potential regulation based on the adsorption interaction between the molecularly imprinted polymer (MIP) on the surface of graphene-modified pencil core electrode (G − PCE) and its template molecules. MIP is synthesized by electropolymerization with 4,4’–DIADPE (as template molecules) and acrylamide (AM, as functional monomer). The results of cyclic voltammetry, N2 adsorption–desorption isotherms, and scanning electron microscopy prove that the presence of these imprinted cavities facilitated excellent selectivity of the sensor. The adsorption mechanism and kinetics for the adsorption of 4,4’–DIADPE on MIP are explored by IPDP. The intra-particle diffusion model shows that a multiple sorption rate is attributed to this adsorption. A pseudo-first-order equation is established, which fits well with the adsorption data, indicating that physical adsorption should be the rate determining processes in adsorption. Meanwhile, nonlinear forms of Langmuir, Freundlich, and Langmuir–Freundlich adsorption isotherm models are used to fit the experimental adsorption curves. It is observed that the Langmuir–Freundlich model provides better data fitting than the other two models. In addition, this MIP − IPDP sensor with good reproducibility, repeatability, and stability exhibits a limit of detection (LOD) of 0.0463 µM. Thus, the proposed MIP − IPDP sensor is successfully applied for the quantitative determination of 4,4’–DIADPE in wastewater with recoveries from 91.63% to 101.21%, which is in agreement with the results obtained by standard high-performance liquid chromatography method.