Glucose in human serum determined by capillary electrophoresis with glucose micro-biosensor

A glucose micro-biosensor was employed as detector in capillary electrophoresis (CE) for determining the concentration of glucose in human serum. The micro-biosensor was based on the immobilization of the SWNTs-glucose oxidase-chitosan biocomposite at a platinized Au electrode by electrodeposition. The influencing factors including separation voltage, detection potential, pH value, and the concentration of the buffer were studied. Suitable conditions were obtained for the determination of glucose: running buffer, 25 mM PBS (pH 8.0); separation field strength, 250 V cm(-1); detection potential, 0.80 V vs. saturated calomel electrode. Under optimized detection conditions, glucose responded linearly from the range of 5 mM to 1 mM with a correlation coefficient of 0.9986 for the injection voltage of 5.0 kV and injection time of 10 s. The concentration limit of detection of the method was 1 mM (S/N 3). The micro-biosensor exhibited good stability and durability in the analytical procedures. The relative standard deviation of the migration time and peak current were 1.7% and 2.6%, respectively. Glucose in human serum from two healthy individuals and two diabetics was successfully determined, giving a good prospect for a new clinical diagnostic instrument.