The acid phosphatase hydrolysis of phenylphosphoric acid (at pH 5 and
at 25 degrees C) with a new type of liquid-immersion surface acoustic
wave enzyme sensor (SAW) is described, A mathematical model was derive
d to estimate the kinetic parameters and to determine the concentratio
ns of enzyme and substrate, The inhibition of the product to the enzym
e activity was involved In the model. The Michaelis constant was estim
ated to be 1.17 x 10(-4) mol l(-1). The recovery of the sensor system
was 97.4-104.4% (n = 6). The effects of temperature and pH on the enzy
me activity were discussed. The proposed model compared favourably wit
h the linear method which indicated that the model gave more precise r
esults.