Differential pulse voltammetric determination of P(V) following adsorptive accumulation of alpha-[PMo(12)O(40)](3-) on a polypyrrole-modified glassy carbon electrode

On the basis of the formation and pre-concentration of an α-Keggin-type [PMo₁₂O₄₀]³⁻ complex, a novel voltammetric method was developed for the determination of trace levels of P(V). The α-[PMo₁₂O₄₀]³⁻ complex was formed by heating a 5×10⁻⁴ M Mo(VI)-0.2 M HCl-40% (v/v) CH₃CN system containing a trace amount of P(V) at 70 °C for 30 min. During the electrochemical polymerization of pyrrole in the α-[PMo₁₂O₄₀]³⁻ solution, the α-[PMo₁₂O₄₀]³⁻ complex was accumulated into the polypyrrole film on a glassy carbon electrode. The differential pulse voltammetric peak current due to the α-[PMo₁₂O₄₀]³⁻ complex incorporated in the polypyrrole film was linearly dependent on the P(V) concentration in the range of 5×10⁻⁹-5×10⁻⁷ M; a detection limit of 2×10⁻⁹ M was achieved.