Glucose determination by differential pulse voltammetry with a platinum electrode.
Measurements with differential pulse voltammetry were carried out using an electrocatalytic glucose sensor based on a three-electrode system with a smooth platinum working electrode in a flow-through-type arrangement. The geometric area of the working electrode was 0.5 mm2. The influence of environmental conditions (temperature, pH, pCO2, pO2) was tested using an appropriate parameter set for differential pulse voltammetry (pulse height between -10 and -100 mV, pulse width 40 ms, scan rate 20 mV/s). Also, investigations were conducted in the presence of co-reactants such as urea and some amino acids. Finally, the electrode was tested in human serum. A sequence of anodic and cathodic pulses (duration 1 s; +1150 mV; -950 mV vs. Ag/AgCl) was used as a short rejuvenation cycle (duration 12 s). The signal mostly dependent on glucose was found in the low potential region around -750 mV vs. Ag/AgCl. The calibration curves were nonlinear above a glucose concentration of 12.5 mmol/l. In the linear range, the sensitivity of the electrode was approximately 60 nA/mmol/l for a pulse amplitude of -10 mV; it increased by one order of magnitude at a pulse height of -80 mV. The presence of amino acids caused a decrease of the sensor current to about 35%. Varying their concentration between 50% and 150% of their average physiological values was without any influence on the measuring signal. A variation of the urea concentration between 2 and 10 mmol/l had an effect of about 12% of the magnitude of the glucose dependent sensor current. We found linear relations between cell current, temperature, and pH, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Temme
J
J
Ilmenau Institute of Technology, Department of Technical and Biomedical Cybernetics, GDR.
Lemke
K
K
D015374:Biosensing Techniques; D001786:Blood Glucose / Q000032:analysis*; D002245:Carbon Dioxide; D004566:Electrodes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010313:Partial Pressure; D010984:Platinum; D011048:Polarography
D001786:Blood Glucose; D002245:Carbon Dioxide; D010984:Platinum