Voltammetric determination of fenitrothion and study of its interaction with DNA at a mercury meniscus modified silver solid amalgam electrode

Abstract

A mercury meniscus modified silver solid amalgam electrode was used for the first time for the determination of submicromolar concentrations of fenitrothion (FNT). The medium of ethanol–Britton–Robinson buffer of pH 7.0 (1:9) was chosen as the optimal one. The newly developed direct current and differential pulse (DP) voltammetric methods are fast, reliable, and robust. Moreover, the applicability of the DP voltammetric method was verified for the determination of FNT in spiked samples of drinking and river water, with the limits of quantification in the concentration order of 10−7 mol dm−3. Furthermore, the interaction of FNT with double-stranded (ds) DNA was investigated directly in a solution. From changes in the FNT electrochemical signals, we assume a formation of a FNT–dsDNA complex in which FNT bounds to dsDNA by electrostatic forces. DP voltammetry was employed to probe this interaction, while cyclic voltammetry was used for the investigation of voltammetric data of free FNT and FNT bound to dsDNA.