Abstract
An amperometric biosensor has been developed for the determination of H sub(2)O sub(2) in plant samples. Horseradish peroxidase (HRP) is immobilized on a sandwiched nano-Au particle/m-phenylenediamine polymer film by glutaraldehyde cross-linking. The film is formulated on the carbon paste electrode (CPE) blended with ferrocene as an electron transfer mediator. On the low concentration range, the current response is related to the H sub(2)O sub(2) concentration linearly from 0 to 8x10 super(-6) M with a detection limit of 1.3x10 super(-7) M. On a wider concentration range of 8x10 super(-6) to 1.4x10 super(-4) M, the reciprocal of current response is linearly related to the reciprocal of H sub(2)O sub(2) concentration. The apparent Michaelis-Menten constant (K sub(m) super(app)) was calculated to be 0.0334 mM. The sensor has been tested by determining H sub(2)O sub(2) concentration in plant leaf samples.