Spectrophotometric cell comprising parallel rotating and stationary bioreactors: Application to the determination of glucose in serum samples

A spectrophotometric cell comprising parallel bioreactors facing each other and containing immobilized enzyme preparations is described. The lower reactor rotates to minimize diffusional constraints, and the upper reactor is fixed to provide an integrated design for the realization of coupled enzyme-catalyzed reactions. The operating characteristics of the cell are illustrated with the determination of glucose using glucose oxidase [EC 1.1.3.4] and horseradish peroxidase [EC 1.11.1.7] as immobilized enzymes (horseradish peroxidase on the rotating reactor and glucose oxidase on the stationary one). The H2O2 produced in the dissolved-oxygen oxidation of β-D-glucose enters into oxidative coupling in a reaction with N,N-dimethylaniline and 4-aminophenazone which is catalyzed by horseradish peroxidase; the absorbance of the colored complex formed provides the basis for monitoring. The cell was incorporated into a continuous-flow/stopped-flow/continuous-flow operation, and the determination was based on the rate of response under stopped-flow conditions. The overall approach was applied to the determination of glucose in standards of human serum and samples of bovine blood serum.