Melamine-imprinted polymer grafts through surface photopolymerization initiated by aryl layers from diazonium salts

In this work, diazonium-based photoinitiators were electrografted on gold electrodes to provide specific, selective and ultrasensitive molecularly imprinted polymer (MIP) grafts for the detection of melamine. This toxic molecule was used as a template, while methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) were the functional and crosslinking monomers, respectively. Surface-initiated photopolymerization was conducted because it is a simple and versatile mean for making ultrathin MIP grafts (∼25 nm thick). Both cyclic and square wave voltammetry (SWV) were used for investigating rebinding melamine by the MIP grafts. However, the latter permitted to achieve ultrasensitive detection down to 7.7 × 10−10 mol/L in PBS and 3.1 × 10−10 mol/L in milk. Recovery was found to be very good, levelling off at 92%.