Electrochemical determination of hemoglobin on a magnetic electrode modified with chitosan based on electrocatalysis of oxygen

A simple biosensor based on a magnetic glassy carbon electrode (MGCE) modified with chitosan (CS) was developed for directly electrochemical determination of hemoglobin (Hb). Hb, as an enzyme-like catalyst, was adsorbed and immobilized by CS membrane on the MGCE to electrochemically catalyze the reduction of dissolved oxygen. In turn, Hb could be determined in terms of the reduction peak current. The biosensor, where Hb adsorbed under an alkaline condition had high electrochemical response, increased by 49.37% compared with Hb adsorption under the neutral conditions. Additionally, the biosensor increased the response by 13.77% under an external magnetic field, which was ascribed to the paramagnetism of Hb and O-2. All the experimental parameters, such as pH, ionic strength and temperature of the electrolyte solution, which influenced on the Hb enzyme-like activity and saturation of dissolved oxygen were optimized. Differential pulse voltammetry (DPV) showed that there was a linear relationship between reduction peak current and the logarithm of Hb concentration. The determination range for Hb were from 0.05 mu g.mL(-1) to 50 mu g.mL(-1) with the detection limit of 0.01 mu g.mL(-1) (S/N = 3). Hb in human blood samples was determined by DPV, the determination results were in good accordance with the reference values from typical clinical analysis.