A maize tassel-multiwalled carbon nanotubes modified glassy carbon electrode for amperometric environmental monitoring of Pb (II) and Cu (II) via horseradish peroxidase inhibition

Abstract

This paper describes the fabrication and application of an inhibition-based enzyme biosensor proposed for environmental monitoring and assessment of heavy metal ions in aqueous solution. A maize tassel-multiwalled carbon nanotube (MT-MWCNT) composite material was prepared and used to immobilize horseradish peroxidase (HRP) on a glassy carbon electrode (GCE) to produce a biosensor responsive to H;(X The biosensor was incubated in heavy metal solutions and the inhibited cathodic response determined amperometrically. The response was linear (R~ > 0.99) over the concentration ranges 0.092 - 0.55 and 0.068 - 2.0 mg/L for Pb:* and Cu:7 respectively, with limits of detection (LOD) values of 2.3 and 4.1 pg/L. Relative error values of 7.93 and 2.55 % were obtained for Pb:" and Cu:+, respectively, when the biosensingtechnique was validated using a standard reference material. Recoveries of 96-104% were obtained when applied to the measurement of PtU and Cu~+ in tap water. The fabricated biosensor exhibited good stability, repeatability and reproducibility.