Serotonin electrochemical detection in tomatoes at MWCNT-AONP nanocomposite modified electrode
Pholoso Calvin Motsaathebe, Omolola E. Fayemi
Abstract
Abstract This work reports on the successful synthesis of antimony oxide nanoparticles (AONPs) by hydrothermal method, acid treatment of multi-walled carbon nanotubes (f-MWCNTs), and fabrication of a MWCNT-AONP nanocomposite on screen-printed carbon electrodes (SPCE) to detect serotonin (5-HT) in tomatoes. The synthesized nanomaterials were all characterized with x-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV–vis) spectroscopy, and transmission electron microscopy (TEM). The electro-analytic and electrocatalytic experiments were performed utilizing square wave voltammetry (SWV) and cyclic voltammetry (CV) methods. The SPCE-MWCNT-AONP modified electrodes showed better electron transport and improved current response towards detection of 5-HT when compared to other electrodes studied. The current response decreased in this manner, the SPCE-MWCNT-AONP (84.13 μ A) > SPCE-fMWCNTs (33.49 μ A) > SPCE-AONPs (24.40 μ A) > SPCE-bare (2.89 μ A). The sensitivity, limit of detection (LoD) and limit of quantification (LoQ) for the SPCE-MWCNT-AONP modified electrode towards 5-HT detection was 0.2863 μ A μ M −1 , 24 .6 nM, and 74 nM respectively, with linearity from 0.016–0.166 μ M (R 2 = 0.9851) utilizing SWV. The acquired LoD value for the proposed sensor compared favorably with other chemically modified electrodes from literature. Furthermore, the proposed sensor showed good reproducibility and excellent anti-interference behavior. Real-sample analysis of 5-HT in tomatoes showed excellent recoveries ranging from 91.32 to 108.28%, with an average RSD (%) value of 2.57 (n = 3). The obtained results strongly suggest that the proposed novel sensor could be applicable in diagnosing point-of-care diseases and therapeutics.