Synthesis of nano-sized arsenic-imprinted polymer and its use as As selective ionophore in a potentiometric membrane electrode: Part 1

In this study, a new strategy was proposed for the preparation of As (III)-imprinted polymer by using arsenic (methacrylate)₃ as template. Precipitation polymerization was utilized to synthesize nano-sized As (III)-imprinted polymer. Methacrylic acid and ethylene glycol dimethacrylate were used as the functional monomer and cross-linking agent, respectively. In order to assembly functional monomers around As (III) ion, sodium arsenite and methacrylic acid were heated in the presence of hydroquinone, leading to arsenic (methacrylate)₃. The nano-sized As (III) selective polymer was characterized by FT-IR and scanning electron microscopy techniques (SEM). It was demonstrated that arsenic was recognized as As³⁺ by the selective cavities of the synthesized IIP. Based on the prepared polymer, the first arsenic cation selective membrane electrode was introduced. Membrane electrode was constructed by dispersion of As (III)-imprinted polymer nanoparticles in poly(vinyl chloride), plasticized with di-nonylphthalate. The IIP-modified electrode exhibited a Nernstian response (20.4 ± 0.5 mV decade⁻¹) to arsenic ion over a wide concentration range (7.0 × 10⁻⁷ to 1.0 × 10⁻¹ mol L⁻¹) with a lower detection limit of 5.0 × 10⁻⁷ mol L⁻¹. Unlike this, the non-imprinted polymer (NIP)-based membrane electrode was not sensitive to arsenic in aqueous solution. The selectivity of the developed sensor to As (III) was shown to be satisfactory. The sensor was used for arsenic determination in some real samples.