Glucose Determination by Means of Steady-state and Time-course UV Fluorescence in Free or Immobilized Glucose Oxidase

Changes in steady-state UV fluorescence emission from free or immobilizedglucose oxidase have been investigated as a function of glucose concentration.Immobilized GOD has been obtained by entrapment into a gelatine membrane. Changes insteady-state UV fluorescence have been quantitatively characterized by means ofoptokinetic parameters and their values have been compared with those previouslyobtained for FAD fluorescence in the visible range. The results confirmed that greatercalibration ranges are obtained from UV signals both for free and immobilized GOD inrespect to those obtained under visible fluorescence excitation. An alternative method tothe use UV fluorescence for glucose determination has been investigated by using timecourse measurements for monitoring the differential fluorescence of the redox forms of theFAD in GOD. Also in this case quantitative analysis have been carried out and acomparison with different experimental configurations has been performed. Time coarsemeasurements could be particularly useful for glucose monitoring in complex biologicalfluids in which the intrinsic UV fluorescence of GOD could be not specific by consideringthe presence of numerous proteins.