الفهرس | Only 14 pages are availabe for public view |
Abstract In this thesis, two electrochemical biosensors were investigated for the determination of mercury ions and dopamine. The mercury biosensor depends on the immobilization of catalase enzyme cross linkage with glutaraldehyde (GA) and bovine serum albumin (BSA) on glassy carbon electrode (cat/GCE). The dopamine biosensor depends on the covalent immobilization of laccase with graphene oxide on glassy carbon electrode (Lac-GO/GCE). The performance characteristics of these biosensors were studied including slope, linear range, detection limit, usable pH, life time. The composition and morphology of the proposed biosensors were studied using several microscopic analysis techniques (e.g. scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electroanalytical performance was determined by using constant potential Amperometry for the mercury biosensor and differential pulse voltammetry (DPV) for the dopamine biosensor. The two biosensors exhibited a good sensitivity with a linear range (0.05 nmol/L to 0.5 nmol/L) and a detection limit of 0.018 nmol/L for the mercury biosensor and a linear range (0.1 æmol/L to 1.0 æmol/L) and a detection limit of 32 nmol/L for the dopamine biosensor. Overall, the mercury and dopamine biosensors showed a good sensitivity and specificity |