Electrochemical detection of 2-naphthol at a glassy carbon electrode modified with Tosflex film

In this study, a Tosflex (a perfluoro-anion-exchange membrane) modified glassy carbon electrode has been used to detect 2-naphthalenol (2-naphthol) in aqueous solutions in order to demonstrate the electroanalytical application of Tosflex. 2-naphthol polymerizes upon electrochemical oxidation at a glassy carbon electrode; however, the current related to this oxidation is too small for analytical purpose at low concentration level. A Tosflex polymer modified glassy carbon electrode (TFGCE) was found of having capability to improve the detection limit because 2-naphthol molecules deprotonated in basic solutions to form 2-naphtholate anions that were accumulated to TFGCE by the anion-exchange characteristic of Tosflex. The accumulated 2-naphtholate anions were determined with the following differential pulse voltammetry. With 3 minutes accumulation at +0.05 V, the dependence of oxidation current versus concentration was linear from 8 x 10(-7) M to 1 X 10(-5) M. with a regression coefficient of 0.999 and a detection limit of 2 x 10(-7) M. Unlike many other anion-exchange polymer modified electrodes, the TFGCE is stable at highly basic condition.