Designing a new material to fabricate electrodes sensitive to ion species of specific interest is the main stream in the ion sensitive electrode research. The research efforts of the present authors have been directed, in particular, to the development of a phosphate ion sensitive electrode based on non-stoichiometric compound Co1-rO and a Cu2+ ion sensitive electrode based on LaB6. In this paper, a new sulfate ion sensitive electrode is reported based on non-crystal Ni-P alloy, which has a very nice response characteristics including stability, selectivity and linear response range. The electrode shows a linear range of response from 1×10-6 to 1 X 10-2 mol/L and a detection limit of 4×10-7mol/L for the sulfate ion. The selectivity coefficients for common anions Cl-, NO3-, H2PO4-, Br- and I- are obtained as 2×10-1, 8×10-5, 8×10-3, 3×10-1 and 4×10-1, respectively. The electrochemical deposition of the non-crystal Ni-P alloy on different matrix materials has been described for preparation of the titled electrode.
