Voltammetric determination of 4-nitrophenol and 5-nitrobenzimidazole using different types of silver solid amalgam electrodes - a comparative study
Abstract
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 mu molL(-1) (DCV) and 0.47 mu molL(-1) (DPV), at m-AgSAE it was 0.32 mu molL(-1) (DCV) and 0.16 mu molL(-1) (DPV), and at MF-AgSAE it was 0.97 mu molL(-1) (DCV) and 0.70 mu molL(-1) (DPV). For 4-nitrophenol at p-AgSAE, L(Q) was 0.37 mu molL(-1) (DCV) and 0.32 mu molL(-1) (DPV), at m-AgSAE it was 0.14 mu molL(-1) (DCV) and 0.1 mu molL(-1) (DPV), and at MF-AgSAE, it was 0.87 mu molL(-1) (DCV) and 0.37 mu molL(-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.