Fabrication of a solid-state ion selective electrode based on polypyrrole conducting polymer for As (V) ion

Abstract

A pencil graphite electrode (PGE) electrodeposited by polypyrrole conducting polymer doped with arsenate ion (PGE/PPy/As) was prepared and used as potentiometric sensor electrode for determination of As(V). Electropolymerisation reaction for preparing of As(V) sensor electrode was carried via applying a constant potential of 0.90 V on PGA as working electrode versus saturated calomel electrode (SCE) in a solution containing 0.40 M pyrrole and 0.030 M Na₂HAsO₄ as electrolyte. The constructed electrode displayed a linear and near Nernstian response (28.25 ± 0.30 mV/decade) to As(V) ions in the concentration range of 5.0 × 10⁻⁵ to 1.0 × 10⁻¹ M. A detection limit of 2.8 × 10⁻⁵ M and a fast response time (≤10 s) was observed during measurements. The working pH range of the electrode was 6.5–10.0 and lifetime of the sensor was at least 60 days.

Keywords:

• As(V)
• electropolymerisation
• polypyrrole
• potentiometry
• solid-state electrode

Acknowledgement

The authors appreciate the Research Department of University of Guilan for partial financial support of this work.

Scheme 1. pH-dependent speciation of As(V) and As(III) at 25 °C.