Insulin is an important polypeptide which controls the glucose level in blood within a narrow concentration range. insulin sensing is great important for clinical diagnostics, because it serves as a predictor of diabetes of insulinoma and trauma.”2 Direct electrooxidatiorof insulin is important for the development of fast and sensitive amperometnc detectors coupled to flow systems or chromatographic instruments for this hormone. Low sensitivity, reproducibility and stability over a wide range of solution compositions and high overpotential at which the insulin oxidation process is occurred are limitations of using the bare and unmodified electrodes as an electrochemical sensor for insulin detection. The chemical modification of inert substrate electrodes with redox active thin films offers significant advantageous in the design and development of the electrochemical insulin sensor. A Sol-gel technique was used for fabrication renewable carbon composite electrode (CCE) modified with nickel powder. In Continuous our studies this modified electrode has been used for oxidation of insulin [1-2 ]. The nickel oxide film electrode was used as an amperometric detector for hydrodynamic amperometry and flow injection analysis of insulin. It is found that calibration curve is linear up to 30 t M with detection limit 0.1 nM under the optimized condition in hydrodynamic amperometry using rotating disk modified CCE. Flow injection amperometric technique can be used for picomolar detection of insulin. This electrode shows many advantageous as an insulin sensor such as simple preparation method without using any specific electron transfer mediator or specific reagent, high sensitivity, excellent catalytic activity, short response time, long term stability and antifouling property toward insulin and its oxidation product. Sensitivity, detection limit and antifouling properties of this insulin senspr are better than all of reports in literature. Additionally it is promising for monito
