In-situ immobilisation of glucose oxidase on a novel microporous silica support

Abstract

Glucose oxidase has been covalently immobilised onto a highly porous, but robust microporous silica structure. The porosity of this microporous structure was adjusted by the inclusion of acetamide to improve the enzyme immobilisation procedure. The covalent enzyme attachment was achieved by an on-line immobilisation procedure in which the reagents were pumped through the support that had been placed in-situ in the reactor tube. Glucose oxidase was immobilised with glutaraldehyde cross-linking to the 3-aminopropyltriethoxysilane treated support. The narrow tube enzyme reactor produced was then incorporated into a flow injection system and its activity tested using the determination of glucose with spectrophotometric detection at 436 nm. A linear calibration range was obtained for glucose between 5 × 10⁻⁴ and 5 × 10⁻³ mol l⁻¹ with a limit of detection of 1.4 × 10⁻⁴ mol l⁻¹. The %RSD was 4% at the 5 × 10⁻⁴ mol l⁻¹ level.