Application of ammonium-selective zeolite for enhancement of conductometric bi-enzyme biosensor for L-arginine detection
Abstract
L-arginine conductometric biosensors were developed on the basis of arginase and ure¬ase cross-linked by glutaraldehyde in a single bioselective membrane and modified with clinoptilo¬lite. The clinoptilolite intrinsic properties helpful for conductometric detection of L-arginine were investigated using three approaches to the creation of zeolite-containing enzymatic membranes. The developed biosensors were compared with the L-arginine biosensor, not modified with clinoptilolite, for the sensitivity, linear and dynamic range, detection limit, response time, operational and storage stability in L-arginine analysis. It was shown that the incorporation of ammonium-selective zeolite to the bioselective membrane of L-arginine biosensor allows increasing the biosensor sensitivity when applying all proposed approaches to the formation of zeolite-containing biomembranes. In addition, excellent values of both detection limit and linear range (1.0×10-5 M and 0.01–6 mM, respectively) were achieved for the biosensor based on arginase, urease and zeolite distributed in a single bioselec-tive layer. The clinoptilolite-based biosensors for L-arginine demonstrated short response time, high operational stability (a coefficient of variations reached 0.74%), their lifetime exceeded four months