Differential Pulse Voltammetric (DPV) Determination of Phosphomolybdenum Complexes by a Poly(Vinyl Chloride) Coated Molybdenum Blue Modified Pencil Graphite Electrode (PVC-MB-PGE)

Abstract

The rapid and accurate determination of phosphate is necessary for human health and the environment. In this study, three species of inorganic phosphate were sensitively determined by the use of poly(vinyl chloride) (PVC)-coated molybdenum blue (MB) modified pencil graphite electrodes (PGEs) for the first time. The prepared electrodes were characterized by electrochemical and microscopic methods. For the determination of inorganic phosphate species, PMo₁₂O₄^3–, PMo₁₁O₃₉H₄^7– and PMo₁₀O₃₈H₈^11– complexes were formed by the interaction of molybdenum blue and phosphate under the optimized conditions. Peaks observed in the differential pulse voltammograms (DPVs) were due to the PO₄^3–, HPO₄^2– and H₂PO₄^– complexes and the number of molybdenum atoms in molybdenum blue. For the electrochemical determination of these complexes, each had an oxidation peak at a distinctive potential in the differential pulse voltammograms. The electrodes also showed good selectivity for the different phosphate species since they formed unique complex structure with phosphate species. The limits of detection and quantitation were determined to be 0.141 µM and 0.47 µM for PO₄^3– (PMo₁₀O₃₈H₈^11–), 0.11 µM and 0.334 µM for HPO₄^2– (PMo₁₂O₄₀^3–), and 0.129 µM and 0.432 µM for H₂PO₄^– (PMo₁₁O₃₉H₄^7–), respectively.

Keywords:

• Differential pulse voltammetry (DPV)
• molybdenum blue
• molybdenum blue
• molybdophosphate complexes
• phosphate ions
• poly(vinyl chloride) coated modified pencil graphite electrode (PVC-MB-PGE)