Immobilization of glucose oxidase and peroxidase and their application in flow-injection analysis for glucose in serum.

Summary

# Editorial Summary Glucose oxidase and horseradish peroxidase were chemically bound to a glass matrix using glutaraldehyde cross-linking, creating an enzyme column capable of detecting blood glucose concentrations in a rapid, automated flow-injection analysis system. The immobilised enzymes retained substantial activity (700–800 U/g for glucose oxidase and 300–400 U/g for peroxidase) and demonstrated excellent analytical performance, with linearity across clinically relevant glucose ranges (20–1000 mg/dL), recovery rates of 95.4–103.5%, and within-batch precision of 0.8–2.2%. Notably, a single enzyme column remained functional for over two months whilst processing 50 samples daily—equivalent to analysing 100+ samples within an hour—with between-batch imprecision ranging from 2.2–4.2%, meeting standards for clinical laboratory analysis. Whilst this 1990 work predates modern point-of-care glucose metres in equine practice, the underlying enzyme-immobilisation principles remain relevant for understanding glucose detection methodologies and may inform development of high-throughput screening systems for equine metabolic assessment, particularly where repeated sampling is required for conditions such as equine metabolic syndrome or insulin dysregulation.

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Key Findings

• •Glucose oxidase and horseradish peroxidase were successfully immobilized on alkylamine controlled pore glass achieving 700-800 U/g and 300-400 U/g activity respectively
• •Flow-injection analysis system demonstrated linear response for glucose detection from 20-1000 mg/dL with 95.4-103.5% recovery
• •Immobilized enzyme column maintained functionality for over 2 months with 50 assays per day, enabling analysis of more than 100 samples per hour
• •Within-batch and between-batch imprecision were 0.8-2.2% and 2.2-4.2% respectively, indicating good analytical precision