FLOW INJECTION MONITORING OF ENZYME REACTIONS ON SOLID SURFACES

Abstract

Optosensing flow injection analysis may be used to monitor enzyme reactionson various types of solid surfaces, e.g., cellulose, Teflon or polypropylene. The surfaces may bein the form ofa pad, a membraneorparticles (in a column). While the enzyme maybe in solution, advantages accrueif it is attached to the solid surface. Traditional enzyme immobilization on surfaces involves chemical bonding reactions, but enzymes may be directly adsorbed onto certain hydrophobic surfaces. The principles of optosensing measurements are presented andapplicationsto cellulose pads and gas barrier membranes for enzyme measurements are reviewed. Recent novel methodsfor derivatizing enzymes for direct adsorption onto fluorocarbon membranesare presented. A new gas sensing (gas gap) membrane is described in which the membraneacts as the actual sensor and notjust a barrier, suitable for optosensing of monitoring enzyme reactions. Preliminary studies of the direct adsorption of urease enzyme onto the membrane are presented. Silica based C-18 particles in a microcolumn are used to adsorb an indicator and native urease enzymé. Optosensing measurementsof urea by measuring transmittance through the particles are presented.