Electrochemical determination of 6-Tioguanine by using modified screen-printed electrode: magnetic core–shell Fe3O4@SiO2/MWCNT nanoparticles

6-thioguanine (6-TG) is an anticancer drug with narrow safe dose range and intense toxic reactions, so it is urgently necessary to evaluate its clinical usage. Therefore, from the point of view of human health control, the 6-TG determination in biological matrices is of great significance. The current attempt was made to produce magnetic core–shell Fe 3 O 4 @SiO 2 /MWCNT nanocomposite (MCFSMW) to construct a novel selective and sensitive electrochemical 6-TG sensor. The characteristics of synthesized nanocomposite were determined by X-ray Diffraction, Fourier Transform Infrared Spectrometry, Scanning Electron Microscopy and Energy-Dispersive X-ray. The sensor fabrication was based on the surface modification of screen-printed electrode (SPE) with MCFSMW (MCFSMW/SPE). The MCFSMW/SPE possessed an appropriate response and an appreciable electrooxidation behaviors toward the 6-TG detection. There was a significant enhancement in the 6-TG electro-oxidation signal on the MCFSMW/SPE surface compared to the bare SPE. The proposed protocol was explored by chronoamperometry, cyclic voltammetry, and differential pulse voltammetry (DPV). The DPV findings clarified a broad linear relationship between the 6-TG concentrations and the peak height ranged from 0.01 to 280.0 µM with a limit of detection as narrow as 1.0 nM. The practical potency of MCFSMW/SPE was confirmed by sensing of 6-TG in the biological matrices.