Poly(safranine T)-deep eutectic solvent/copper oxide nanoparticle-carbon nanotube nanocomposite modified electrode and its application to the simultaneous determination of hydroquinone and catechol

This work presents the combined use of safranine (SF) as a redox polymer and multiwalled carbon nanotubes (MWCNT)-copper oxide nanoparticles (CuO) in the development of a novel sensor for the simultaneous analysis of hydroquinone (HQ) and catechol (CAT). Electropolymerisation of SF was carried out in acid-doped ethaline deep eutectic solvent to prepare poly(safranine) (PSFEthaline) film electrodes with three different nanostructured architectures on pencil graphite electrodes (PGE) as electrode substrate. The polymerisation was done after nanomaterial surface modification to obtain PSFEthaline-HCl/MWCNT/PGE, PSFEthaline-HCl/CuO/PGE, and PSFEthaline-HCl/MWCNT-CuO/PGE. The synthesis, preparation, and characterisation of PSF film-coated electrodes were studied using cyclic voltammetry and electrochemical impedance spectroscopy to investigate the contribution of each nanomaterial on sensor performance. The best result for polymer film growth was obtained with PSF electrodeposited on MWCNT-CuO/PGE in HCl doped-ethaline. The analytical performance of the modified electrode was evaluated for electrochemical sensing of HQ and CAT by differential pulse voltammetry in aqueous Britton-Robinson buffer solution. Due to the combined effect of MWCNT-CuO nanocomposite film and PSF, the modified electrode sensor provided sensitive and selective detection of HQ and CAT with good peak separation. The simultaneous determination of HQ and CAT in both tap water and milk samples was successfully carried out to demonstrate the analytical applicability of the sensor. The sensor could be a promising analytical approach for monitoring the amount of HQ and CAT in real samples.

Automated summary

This study presents a novel sensor for the simultaneous analysis of hydroquinone (HQ) and catechol (CAT), which utilizes safranine as a redox polymer and multiwalled carbon nanotubes-copper oxide nanoparticles as nanostructures. The sensor shows sensitive and selective detection of HQ and CAT, making it a promising analytical approach for monitoring their amounts in real samples.