Phosphate ion sensor using a cobalt phosphate coated cobalt electrode

A phosphate ion selective electrode coated with cobalt phosphate hydrate was produced. This electrode responds to the activity of H2PO4−, and it exhibited a linear response to H2PO4− in the concentration range from 1.0 × 10−5 to 1.0 × 10−1 mol dm‒3 at a pH range from 4 to 7 with a slope of −39 mV dec−1.234