Composite film of carbon nanotubes and chitosan for preparation of amperometric hydrogen peroxide biosensor.

A new amperometric biosensor for hydrogen peroxide was developed based on cross-linking horseradish peroxidase (HRP) by glutaraldehyde with multiwall carbon nanotubes/chitosan (MWNTs/chitosan) composite film coated on a glassy carbon electrode. MWNTs were firstly dissolved in a chitosan solution. Then the morphology of MWNTs/chitosan composite film was characterized by field-emission scanning electron microscopy. The results showed that MWNTs were well soluble in chitosan and robust films could be formed on the surface. HRP was cross-linked by glutaraldehyde with MWNTs/chitosan film to prepare a hydrogen peroxide biosensor. The enzyme electrode exhibited excellent electrocatalytic activity and rapid response for H(2)O(2) in the absence of a mediator. The linear range of detection towards H(2)O(2) (applied potential: -0.2V) was from 1.67 x 10(-5) to 7.40 x 10(-4)M with correction coefficient of 0.998. The biosensor had good repeatability and stability for the determination of H(2)O(2). There were no interferences from ascorbic acid, glucose, citrate acid and lactic acid.