Serotonin electrochemical detection in tomatoes at MWCNT-AONP nanocomposite modified electrode

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 μA) > SPCE-fMWCNTs (33.49 μA) > SPCE-AONPs (24.40 μA) > SPCE-bare (2.89 μA). 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 μA μM−1, 24.6 nM, and 74 nM respectively, with linearity from 0.016-0.166 μM (R2 = 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.