Selective phosphate sensing using copper monoamino-phthalocyanine functionalized acrylate polymer-based solid-state electrode for FIA of environmental waters

A novel solid-state selective sensor for mono-hydrogen phosphate (HPO4)−2 based on copper monoamino phthalocyanine (CuMAPc) ionophore covalently attached to poly (n-butyl acrylate) (PnBA) has been developed and potentiometrically evaluated. The all solid-state sensor was constructed by the application of a thin film of a polymer cocktail containing a CuMAPc–PBDA ionophore and benzyl-dimethylhexadecyl ammonium chloride (BDMHAC) as a lipophilic cationic additive onto a gold electrode pre-coated with the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) as an ion and electron transducer. The sensor with 14.31 % of CuMAPc-PnBA (ionophore II) exhibited a good selectivity for (HPO4)−2. The thus constructed sensor discriminated many anions, including F−, Cl−, Br−, I–, CH3COO−, NO3−, ClO4−, and SO42−. The potentiometric response of the phosphate selective electrode was found to be independent of the pH of sample solution in the range 6–9. The sensor showed a Nernstian slope of −29.8 ± 0.3 mV conc.−1 decade−1 with linear range of 4.0 × 10−9–1.0 × 10−2 mol L−1 and detection limit of 1.0 × 10−9 mol L−1 at pH 8.0. The proposed phosphate sensor has been utilized as a detector for the flow injection potentiometric determination of phosphate in different water samples at the nanomolar concentration range.