Synthesis of nano-sized hydrogen phosphate-imprinted polymer in acetonitrile/water mixture and its use as a recognition element of hydrogen phosphate selective all-solid state potentiometric electrode

Abstract

Herein, a new recipe is introduced for the preparation of hydrogen phosphate ion-imprinted polymer nanoparticles (nano-IIP) in acetonitrile/water (63.5:36.5) using phosphoric acid as the template. The nano-IIP obtained was used as the recognition element of a carbon paste potentiometric sensor. The IIP electrode showed a Nernstian response to hydrogen phosphate anion; whereas, the non-imprinted polymer (NIP)-based electrode had no considerable sensitivity to the anion. The presence of both methacrylic acid and vinyl pyridine in the IIP structure, as well as optimization of the functional monomers-template proportion, was found to be important to observe the sensing capability of the IIP electrode. The nano-IIP electrode showed a dynamic linear range of 1 × 10^-5 -1 × 10^-1 mol L-1, Nernstian slope of 30.6 ± (0.5) mV decade ^-1 , response time of 25 seconds, and detection limit of 4.0 × 10^-6 mol L^-1 . The utility of the electrodes was checked by potentiometric titration of hydrogen phosphate with La³⁺ solution.

Keywords: hydrogen phosphate; imprinted polymer; ion selectivesolid state; nano-sized.