Determination of methylparaben by differential pulse voltammetry using a glassy carbon electrode modified with polypyrrole

A new modified glassy carbon electrode ( GCE ) based on a synthesized polypyrrole ( PPy ) was developed for the determination of methylparaben by differential pulse voltammetry ( DPV ). PPy was covalently immobilized on GCE surface using tetraethyl ammonium perchlorate ( TEAP ) and acetonitrile ( ACN ). Methylparaben was oxidized by differential pulse voltammetry and a peak was observed at 1.20 V. The calibration curve obtained with differential pulse voltammetry was linear in the concentration range from 0.01 to 5 mM methylparaben with a limit of detection of 8 ×10 −3 mM and RSD of 0.11%. The improved method was applied to the determination of methylparaben in cream samples using the differential pulse voltammetry method.