Preparation of new polymethylmethacrylate-silica gel anion exchange composite fibers and its application in making membrane electrode for the determination of As(V)

Polymethylmethacrylate-silica gel (PMMA-silica gel) organic-inorganic anion-exchange composite fibers were prepared by simple stirring with magnetic bar in different stoichiometric ratios of polymethylmethacrylate (PMMA) and silica gel. The structure and morphology of the prepared composite fibers were ascertained by Fourier transform spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and elemental analysis (CHN/O). The material was found to be highly desirable for electroanalytical application as ionic sensor, its membrane electrode has been developed for the detection of As(V) in solutions. The membrane electrode shows the best result with linear potential response in the concentration range of 1×10^-1molL^-1 to 1×10^-8molL^-1 of As(V) ion with a slope of 30.78mV/decade. The useful pH of the electrode is 5.5-10.0. The selectivity coefficient values for interfering ions indicate good selectivity for As(V) over interfering anions. The accuracy of the procedure has been tested on arsenic-free drinking water samples spiked with known amount of arsenate and results were comparable to those generated by Portable Coulometric Analyzer (PCA-Arsenomat).