Copper-decorated covalent organic framework covalently modified 3D-printed nanocarbon electrodes for the determination of methotrexate

3D printing has emerged as a popular topic in electrochemistry due to its high flexibility in production. In this work, we used graphene/polylactic acid materials for the fabrication of 3D printed electrodes (3DEs) via fused deposition modeling (FDM). Subsequently, the synthesized novel copper-decorated covalent organic framework (Cu(II)@S-COF) was covalently bound on the 3DE by the Au-S bonding to construct the Cu(II)@S-COF@Au@3DE sensor. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and contact angle experiments were used to characterize the prepared 3DEs. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical performance of the prepared 3DEs. The sensor exhibited good electrocatalytic performance for detecting methotrexate (MTX). It was capable of accurately determining MTX in the range from 0.5 to 100 μM with a limit of detection (LOD) of 0.07 μM and a sensitivity of 0.1489 μA μM −1 cm −2 . In addition, the sensor has recoveries from 97.33% to 101.09% for the detection of MTX in commercial tablets and urine samples, so it can be used to detect MTX in real samples successfully. This work opens a novel avenue for using metal-decorated COF materials in the field of electrochemistry.