Urease immobilized polypyrrole/multi-walled carbon nanotubes composite biosensor for heavy metal ions detection

Abstract

Abstract

Facile synthesis of polypyrrole (PPy) and functionalized multi-walled carbon nanotubes (MWCNT) composite deposited urease immobilized stainless steel electrode used for heavy metal ions detection in water is reported in this article. The nanocomposites of PPy and functionalized MWCNT were electrochemically synthesized on stainless steel in 0.1 M aqueous solution of dodecylbenzene sulfonic acid. Different weight% of functionalized MWCNT with respect to pyrrole was used to fabricate nanocomposite films. The films deposited on electrode were used for the immobilization of urease. The immobilization was done by cross-linking 2 mg/mL urease via 0.1% glutaraldehyde at 0.1 M phosphate buffer with 7.0 pH. The synthesized nanocomposites were characterized using cyclic voltammetry, Fourier transform infrared spectroscopy and scanning electron microscopy. After standardization, the urease biosensors have been used to detect heavy metal ions of different concentrations. The detection limit for cadmium and lead was found to be in the range of 1–10 mM.

Keywords:

• polypyrrole
• multi-walled carbon nanotubes
• nanocomposites
• biosensor
• enzyme immobilization