Nanocomposite of graphitized and carboxylated multi-walled carbon nanotubes and chitosan for the highly sensitive detection of niclosamide

Herein, we reported an efficient ultrasound-assisted method to synthesize the nanocomposite of graphitized and carboxylated multi-walled carbon nanotubes and chitosan (GCMCN@CTS), which was used to fabricate the GCMCN@CTS/GCE sensor for the detection of niclosamide (NA). GCMCN with graphitization and carboxylation possessed excellent electrical conductivity and high specific surface area. Graphitization enhanced the electrical conductivity of carbon nanotubes, and carboxylation improved the dispersion degree of carbon nanotubes. CTS with good biocompatibility possessed strong adsorption ability and superior film-forming property. Moreover, the introduction of CTS facilitated the uniform dispersion of GCMCN, and GCMCN with excellent electrical conductivity could make up for the poor electrical conductivity of CTS. Benefitting from the functional collaboration of GCMCN and CTS, an ultra-low detection limit of 1.4 nM could be achieved at the fabricated GCMCN@CTS/GCE sensor in linear NA concentration range of 0.01–10 μM. Moreover, the proposed sensor showed satisfactory reproducibility, repeatability, and anti-interference performance. When used for NA detection in tap water and lake water samples, the GCMCN@CTS/GCE sensor exhibited gratifying recoveries of 96.0–103.8% with RSD values of 2.0–4.7%.