A high effect polymer-free covalent layer by layer self-assemble carboxylated MWCNTs films modified GCE for the detection of paracetamol

This work presents an excellent strategy to assemble a new carboxylic acid functionalized multi-wall carbon nanotubes (CMWCNTs) thin film via layer by layer (LBL) covalent bond by using ethylenediamine as an arm linker. Scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy were used to characterize the assembly process. Electrochemical studies indicated that the modified electrode possesses a remarkably electrocatalytic activity toward paracetamol at a lower potential compared with the bare glass carbon electrode (GCE), and without the need for redox mediators. The thickness of the film assembled CMWCNTs is easily controlled by changing the numbers of the cycles in the LBL assembly process, which also effectively tuned the electrocatalytic activity of the film toward paracetamol. The experiments result display that the six layers film performs the best electrocatalytic activity to paracetomol. The constructed electrode with six layers showed a good sensitivity of 2.293   μA   M −1   cm −2 in the linear range of 1–200   μM, and a detection limit of 0.092   μM ( S / N   =   3). Furthermore, the CMWCNTs film also showed good selectivity and excellent stability for the determination of paracetamol.