2-(Anthracen-9-yl)benzothiazole-modified graphene oxide-nickel ferrite nanocomposite for anodic stripping voltammetric detection of heavy metal ions.

A novel electrochemical sensor, 2-(anthracen-9-yl)benzothiazole (ABT)-modified nickel ferrite reduced graphene oxide (NF@rGO) has been designed for the individual and simultaneous detection of Cd2+, Cu2+, and Hg2+ ions. Herein, NF@rGO nanocomposite, synthesized by a simple hydrothermal methodology, was hooked to ABT under easy and simple stirring conditions. Chelation of active functional groups of ABT with metal ions was augmented with higher adsorption and conductivity provided by NF@rGO. The created synergy resulted in analytical signals via selective oxidation of the ions within a potential ranging from - 1.2 to + 1.2 V vs sat. KCl. The proposed protocol exhibited a wide linear range from 0.05 to 1250 nM with excellent detection limit of 123, 54.1, and 86.6 pM via anodic stripping voltammetry for the simultaneous determination of Cd2+, Cu2+, and Hg2+ ions, respectively. Simple cost-effective synthetic approach, improved sensitivity with high selectivity, noteworthy repeatability (RSD less than 3%), and reproducibility (RSD less than 7%) equipped with successful real time monitoring (apparent recovery more than 90%) bring about a spiffing sensing platform for the detection of hazardous metal ions.

Electrochemical detection of methyl parathion via a novel biosensor tailored on highly biocompatible electrochemically reduced graphene oxide-chitosan-hemoglobin coatings.

A quick electrochemical sensing tool by utilizing novel bioelectrode based on redox active protein hemoglobin (Hb) has been offered here for the determination of methylparathion (MP). The bioelectrode has been designed by immobilizing Hb on electrochemically reduced graphene oxide-chitosan (ERGO-CS/Hb/FTO) based biocompatible coatings. Fourier transform-infrared analyses (FTIR), field emission scanning electron microscopy (FESEM), UV-visible and electrochemical characterization reveal the successful grafting of ERGO-CS/Hb/FTO. A detailed impedimetric analysis shows low charge transfer resistance (RCT) and solution resistance (Rs) for the fabricated biosensor, thus pointing towards improved electrochemical performance and sensitivity. In-depth elucidation of redox analysis has been presented in terms of surface concentration of redox moiety (2.92 × 10-9 mol cm-2) and heterogeneous electron transfer rate constant (0.0032 s-1) which indicate enhanced surface coverage and better charge transfer properties of the proposed electrochemical biosensor. The sensor is equipped with a low limit of detection of 79.77 nM and a high sensitivity of 45.77 Acm-2 µM-1 with excellent reproducibility. The modified biosensor also offered its credibility towards detection of MP in vegetable samples with recovery (%) ranging from 94% to 101%. The designed biosensor hereby, evolves as a promising approach for the recognition of MP.