Dynamic model of an optical absorption-based pH sensor

Abstract

A mathematical model of an optical absorption-based pH sensor is described. Emphasis is placed on the influence of the parameters of the sensor and the pH on the dynamic characteristics of the sensor. It is shown that the response is ‘non-symmetrical’, i.e., the response time when pH_initial– pH_final > 0 is not equal to the response time when pH_initial– pH_final < 0. This theoretical result was confirmed by experiment. The influence of different parameters, viz., pK_ind, ε diffusion coefficient and thickness of the membrane, was also investigated.