Voltammetric Determination of 4‐Nitrophenol and 5‐Nitrobenzimidazole Using Different Types of Silver Solid Amalgam Electrodes – A Comparative Study

The voltammetric behavior of two genotoxic nitro compounds (4‐nitrophenol and 5‐nitrobenzimidazole) has been investigated using direct current voltammetry (DCV) and differential pulse voltammetry (DPV) at a polished silver solid amalgam electrode (p‐AgSAE), a mercury meniscus modified silver solid amalgam electrode (m‐AgSAE), and a mercury film modified silver solid amalgam electrode (MF‐AgSAE). The optimum conditions have been evaluated for their determination in Britton‐Robinson buffer solutions. The limit of quantification (L_Q) for 5‐nitrobenzimidazole at p‐AgSAE was 0.77 µmol L^?1 (DCV) and 0.47 µmol L^?1 (DPV), at m‐AgSAE it was 0.32 µmol L^?1 (DCV) and 0.16 µmol L^?1 (DPV), and at MF‐AgSAE it was 0.97 µmol L^?1 (DCV) and 0.70 µmol L^?1 (DPV). For 4‐nitrophenol at p‐AgSAE, L_Q was 0.37 µmol L^?1 (DCV) and 0.32 µmol L^?1 (DPV), at m‐AgSAE it was 0.14 µmol L^?1 (DCV) and 0.1 µmol L^?1 (DPV), and at MF‐AgSAE, it was 0.87 µmol L^?1 (DCV) and 0.37 µmol L^?1 (DPV). Thorough comparative studies have shown that m‐AgSAE is the best sensor for voltammetric determination of the two model genotoxic compounds because it gives the lowest L_Q, is easier to prepare, and its surface can be easily renewed both chemically (by new amalgamation) and/or electrochemically (by imposition of cleaning pulses). The practical applicability of the newly developed methods was verified on model samples of drinking water.