A poly(dimethylsiloxane)-based electrochemical cell coupled with disposable screen printed edge band ultramicroelectrodes for use in flow injection analysis

We report here the development of an inexpensive poly(dimethylsiloxane) (PDMS)-based electrochemical cell specifically designed for disposable screen printed edge band ultramicroclectrodes (SPUMEs) for use in flow injection analysis (FIA). The SPUME is fabricated with a built-in three-electrode pattern on a non-conducting polypropylene substrate. The edge of the carbon and/or metal-sandwiched films between the insulator layers can serve as a band type ultramicroelectrode. Fabrication of the cell is straightforward; no micromechanical operation is included. Simply by molding of PDMS with a "T" type channel to fix the SPUME in a confined wall-jet-type configuration, the performance characteristic of the proposed cell was evaluated by using the Fe(CN)(6)(3-)/Fe(CN)(6)(4-) redox couple. The high velocity jet of solution resulted in a mass transport coefficient up to ca. 0.48 cm/s. The proposed FIA system was applied for the detection of nitrite and the current response was linear up to 700 mu M with a detection limit of 0.067 mu M (S/N = 3). Finally the determination of nitrite in lake and ground waters without the addition of supporting electrolyte was successfully demonstrated. (C) 2007 Elsevier B.V. All rights reserved.