Glucose determination in samples taken by microdialysis by peroxidase-catalyzed luminol chemiluminescence

An automatic, luminometric assay of glucose in samples of the extracellular water space obtained by microdialysis is described. The assay involves oxidation by glucose oxidase (EC 1.1.3.4) and mutarotation of glucose by aldose mutarotase (EC 5.1.3.3.). The H2O2 formed is subsequently determined in a reaction catalyzed by horseradish peroxidase (EC 1.11.1.7) using luminol as electron donor. The assay is linear between 0.01 and 1 nmol in the cuvette. The detection limit, defined as 3 standard deviations of the reagent blank, was 0.008 mumol/liter in the cuvette. A complete oxidation of glucose is obtained within 4 min and 25 samples are automatically assayed within 75 min. Addition of microdialysate sample obtained from human adipose tissue in vivo did not interfere with the standard curves. Glucose added to microdialysate resulted in a complete recovery compared to a H2O2 standard. Analytical interference from different factors was investigated. No interference was observed up to the following concentrations: 5 mumol/liter epinephrine, 1 mumol/liter norepinephrine, 100 mumol/liter insulin, 500 mumol/liter pyruvate, 50 mmol/liter lactate, and 1 mumol/liter ascorbate. The glucose values with the present method correlated strongly (r = 0.984) with values obtained using a routine method involving glucose oxidase and peroxidase.