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%.