Restricted access copper imprinted poly(allylthiourea): The role of hydroxyethyl methacrylate (HEMA) and bovine serum albumin (BSA) on the sorptive performance of imprinted polymer

Abstract

In this study, imprinted polymers based on copper imprinted poly(allylthiourea) synthesized in acetonitrile (ACN) (Cu2+)-IIP(ACN) or ethanol (EtOH) (Cu2+)-IIP(EtOH) and the effect of 2-hydroxyethyl methacrylate (HEMA) and bovine serum albumin (BSA) on the surface of polymers towards simultaneous preconcentration of Cu2+ and macromolecule exclusion was assessed. Characterization of polymers was carried out by means of Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), textural data [surface area (SBET), total pore volume (VT) and average pore diameter (Dp)], swelling analysis, wettability measurement and determination of point zero charge (PZC). It was noticed that (Cu2+)-IIP(ACN) showed higher porosity than the one (Cu2+)-IIP(EtOH). From the competitive sorption, relative selectivity coefficient (k′) higher than one unit was obtained by comparing (Cu2+)-IIP(ACN) with non-imprinted polymer [NIP(ACN)] over a range of foreign metal ions with same charge and similar ionic radius, thus confirming the imprinting effect created during polymer synthesis. It was also found that the hydrophilic co-monomer (HEMA) as well as the larger molecule BSA coating on (Cu2+)-IIP(ACN) decreases accentually the selectivity of sorbent. On the other hand, the sorbent (Cu2+)-IIP-HEMA-BSA(ACN) demonstrated great capability in promoting simultaneously the sorption of Cu2+ and exclusion of BSA in solution at pH 4.50, thus showing potential application perspectives for the development of matrix interference-free enrichment method towards Cu2+ determination in complicated matrices, such as biological fluids and food samples without implementing common sample treatments based on acid digestion.