This work reports a comparative electrochemical behaviour study and p-nitrophenol analytical detection using silver solid amalgam, hanging dropping mercury, and silver electrodes. For this, square wave voltammetry was employed, where the analytical responses and the redox mechanisms could be compared for reduction processes of 4-nitrophenol by analysis of the voltammetric responses. The analytical performance of the electrode was evaluated and detection and quantification limits, recovery percentages, repeatability, and reproducibility for the silver solid amalgam and hanging dropping mercury electrodes presented similar values; the results presented for the silver electrode indicated worse analytical parameters than the other electrodes. The results indicate that the silver solid amalgam electrode can be considered a suitable tool and an interesting alternative for the analytical determination of 4-nitrophenol, as well as for the determination of other biological and environmentally interesting compounds that present analytical responses on mercury surfaces. 1. Introduction The compound 4-nitrophenol (4-NP) is a nitro-aromatic that is frequently encountered as a product of the degradation or fabrication process of rubber chemicals, lumber preservatives, car exhausts, industrial wastes and also as the main degradation product of organophosphorous pesticides, such as fenitrothion and parathion. Due to the characteristics of its biorefractory compounds, it is considered a hazardous pollutant with toxic effects on human health and the environment [1]. As a result, in the last few years, numerous methodologies have been developed for the analytical determination of 4-NP in different samples. These procedures have involved the use of high-performance liquid chromatography [2], gas chromatography [3], capillary zone electrophoresis [4], and spectrophotometry with flow-injection analysis [5]. Meanwhile, various electroanalytical techniques also have been used with success as alternatives to chromatographic and spectroscopic techniques. For this, different solid surface electrodes, either bare or modified with different organic and inorganic compounds, have been designed to evaluate the analytical responses and to study the redox process mechanisms of the 4-NP [6–8]. Nevertheless, in this type of electrode, the renovation of the electrodic surfaces can be complicated due to the memory effects associated with the strong adsorption processes of organic compounds, which, in general, result in a decrease in the reproducibility of voltammetric responses. Several
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