A response model for surface acoustic wave enzyme sensor applied to the kinetic study of urease-catalytic reaction and urea determination

Abstract

A binary substrate-enzyme complex response model based on a surface acoustic wave (SAW) enzyme sensor has been derived to study enzymatic-catalytic reactions. It is applied to a non-linear least squares metho based on Marquardt algorithm by fitting urease-catalytic reaction data. The effect of initial values of rate constants on the programme convergence of the proposed method is discussed. The kinetic parameters have been estimated and these are of the same order of magnitude as those reported in the literature. As a comparison, the substrate (urea) concentration has been analyzed by the proposed method, the calibration method and the iterative Kalman filter method .The recovery in the case of the proposed method ranges from 98.0% to 103.2% while that for other two methods is in the range of 96.0- 104.4% and 97.2-103.8% respectively. These methods are also used to determine the urea content in human blood. The proposed method compares favourably with other methods and gives more precise results.