Construction of the Polysensor Device

Overview

The project has been designed for water quality testing as it develops sensors for measuring ionic contaminants and some physical parameters.

Details

The current device is capable of measuring simultaneously 6 parameters such as pH, NO3-, Cl-, Electrical Conductance (EC), Total Dissolved Solids (TDS), and salinity. The changes in conductance between two electrodes based on Ohm’s Law are detected by the conductometric sensor. Between the two electrodes is a conducting polymer known as polyaniline and its conductance is sensitive to pH in its normal form. Any chemical reaction involving change of pH can be detected. The conformation change or secondary doping is the other process which affects the conductance of the polymer. A specific receptor is immobilized in the polymer matrix if the chemical reaction does not involve any change in hydrogen ion, as the analyte binds with receptor.

The change in the potential of the electrodes based on the Nernst Law is detected by the potentiometric sensor. This law associates the concentration of the analyte with the equilibrium potential. The concentration of the analyte can be determined by measuring the equilibrium of the electrode, if the electrode is specific for a particular analyte.