Determination of heavy metal ions by an amperometric biosensor based on glucose oxidase immobilized onto single-walled carbon nanotubes/Nile blue nanocomposite

An enzymatic electrochemical biosensor was prepared based on glucose oxidase (GOD) immobilized on single-walled carbon nanotubes/Nile blue (Nb–SWCNTs) nanocomposite cross-linked with glutaraldehyde on graphite electrode. The function of glucose biosensor is based on the electrocatalytic reduction of H 2 O 2 generated by the reaction of the enzyme with glucose molecules. The biosensor was characterized by Fourier transform infrared (FTIR) spectroscopy, emission scanning (FESEM), UV–Vis spectrometry, and voltammetric and amperometric methods. Parameters influencing the performance of the biosensor, namely pH and applied potential, were optimized. Inhibition was carried out for the detection of Hg 2+ and Pb 2+ species under optimized condition. Inhibition investigations showed that the type of inhibition for both the abov- mentioned heavy metal ions were reversible and competitive.