SOLID-PHASE DETERMINATION OF GLUCOSE IN WHOLE-BLOOD

A solid-phase determination of glucose in whole blood has been develop ed that employs an immobilized substrate and aqueous enzymes. A phenol , 3-hydroxyphenylacetic acid, was covalently bonded to micron-size por ous glass beads, and the derivatized beads were reacted with the oxidi zed form of horseradish peroxidase and 4-aminoantipyrine to give a sur face-bound, red quinoneimine dye. The surface color was quantitatively determined by diffuse reflectance spectrophotometry. Hydrogen peroxid e, which oxidizes the enzyme, was determined with a linear range of 10 to 200 mu M and a standard deviation of +/-10 mu M. Samples containin g glucose were treated with glucose oxidase to convert the glucose to hydrogen peroxide. Glucose standards showed a linear range of 50 to 20 0 mg/dL and a standard deviation of +/-9 mg/dL. Results for control se ra were in good agreement with values obtained by the usual aqueous me thod. After correcting for the blood hematocrit, glucose concentration s found for paired plasma and whole blood samples were in good agreeme nt.