“…This transduction can be carried out through a variety of physical and chemical principles, and in most cases, the resultant electrical quantity can be measured using a multimeter. Colorimetric (Acharya, Jayaraman, 1995;Richter, Rocha, Angnes, 2004;Rossi, He, Tubino, 2000;Wang, 2000), potentiometric (Barnard, 1968;Ooba, 1991;Richter, 2003;Sevilla, Alfonso, Andres, 1993;Vreman, 1994;Watanabe, 1997) and conductometric (Sevilla, Alfonso, Andres, 1993;Yue, Ngin, Hailin, 1996) systems based on a multimeter have been described in the literature.…”