Analytical Sciences

Voltammetric Determination of Dinitronaphthalenes Using a Silver Solid Amalgam Paste Electrode

Jana TVRDIKOVA, Ales DANHEL, Vlastimil VYSKOCIL, and Jiri BAREK

Department of Analytical Chemistry, Faculty of Science, Charles University in Prague, UNESCO Laboratory of Environmental Electrochemistry, Hlavova 8, Prague 2, 12843, Czech Republic

The electrochemical behavior and application of a new sensor, a silver solid amalgam paste electrode (AgSA-PE), based on the mixture of a fine silver solid amalgam powder (60:40 (w_Hg/w_Ag)) and a suitable organic pasting liquid (Paraffin oil) in a ratio of 20:1 (w/w), was investigated in an aqueous–methanolic media (1:1). This alternative working electrode provides simple preparation and handling, adequate mechanical stability, easily renewable electrode surface, sufficiently wide cathodic potential window (up to −1200 mV within a pH range of 2.7 – 12.3), and sufficient sensitivity without any necessary pretreatment. The practical usability of the AgSA-PE was verified by the development of voltammetric methods for the determination of selected environmentally important pollutants (1,3-, 1,5-, and 1,8-dinitronaphthalenes) in an aqueous–methanolic media (1:1). The differential pulse voltammetric methods at AgSA-PE give linear concentration dependences in the range of 1 – 100 μmol l⁻¹ with limits of detection of about 1 μmol l⁻¹ in a mixture of Britton–Robinson buffer of appropriate pH and methanol (1:1).

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