Diazonium functionalized exfoliated graphitic carbon as a binderless and covalently modified electrochemical interface for mercury sensing

A sensitive and selective electrochemical sensing platform for mercury quantification at picomolar level has been described. The interface was constructed using exfoliated graphitic carbon covalently functionalized with mercaptobenzothiozole (MBT) as a selective indicator species in mercury determination. It was characterized using Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) techniques and subsequently used in the fabrication of surface renewable binderless bulk modified robust pellet electrode. The fabricated electrode was used in the measurement of mercury in alkaline medium using differential pulse anodic stripping voltammetry (DPASV). The developed interface showed linearity in the concentration range 1-20 pM with a detection limit of 1 pM. The analytical utility of the proposed interface has been validated by determining the mercury levels from various water and industrial effluent samples with least interference from commonly encountered cations and anions that are generally present in industrial effluents. The storage stability of the proposed interface has been studied over a period of 6 months and the results were found to be highly reproducible with a relative standard deviation of ±6. © 2013 Elsevier B.V

Covalent modification of glassy carbon spheres through ball milling under solvent free conditions: A novel electrochemical interface for mercury(II) quantification

A simple and green chemistry protocol has been proposed based on the covalent anchoring of benzamide molecule on glassy carbon spheres through ball milling under solvent free condition. The modification proceeds through the formation of an amide bond between carboxylic group of glassy carbon spheres and the amino group of modifier molecule. The formation of covalent bond was ascertained using X-ray photoelectron spectroscopy. Scanning electron microscopy was used to study the surface morphology of milled glassy carbon spheres. The aqueous colloidal solution of modified glassy carbon spheres was used in the preparation of thin film electrodes and subsequently used as a novel electrochemical interface in the quantification of mercury at trace level using a differential pulse anodic stripping voltammetric technique. The modified electrode showed good sensitivity and selectivity towards mercury with a detection limit of 1 nM with least interference from most of the ions. The analytical utility of the proposed electrode has been validated by determining the mercury levels in number of sample matrices. © 2014 Elsevier B.V