A miniaturized electrode system for voltammetric determination of electrochemically reducible environmental pollutants
Abstrakt
A newly designed miniaturized electrode system (MES) based on a mercury meniscus modified silver solid amalgam electrode as the working electrode was developed for voltammetric determination of electrochemically reducible organic compounds in small sample volumes. Genotoxic 2-aminofluoren-9-one (2-AFN) was chosen as a model environmental pollutant in this study to test the performance of the introduced MES.
The determination of 2-AFN was carried out by differential pulse voltammetry in 100 mu l, samples under following conditions, using two different ways of air oxygen removal: (i) a supporting electrolyte methanol-Britton-Robinson (BR) buffer of pH 4.0 (1:9, v/v), with regeneration potentials E-reg,1 = 0 mV and E-reg,E-2 = -1200 mV and with oxygen removal by bubbling with nitrogen, and (ii) a supporting electrolyte methanol-BR buffer of pH 10.0 (1:9, v/v), with regeneration potentials E-reg,E-1 = 200 mV and E-reg,E-2 = -1600 mV and with oxygen removal by the addition of solid sodium sulfite as a reducing agent. The calibration curves were measured in the concentration range from 1 to 100 mu mol L-1 of 2-AFN, with the limits of quantification about 1 mu mol L-1 reached in both media.
The practical applicability of the newly developed voltammetric methods using the MES was successfully verified on the direct determination of 2-AFN in model samples of drinking and river water.