Biotechnology Methods » Tools and Techniques in Biological Studies
Conductivity Meter
Conductivity of any substance or solution is measured on the basis of Ohm’s
law (V = I·R).
Conductance = 1/Resistance = 1/R = G
A different type of electrode is used in the conductivity meter compared to
the pH meter
G is proportional to the area A of the faces or electrode, and inversely
proportional to the distance between them. Resistance (R) is expressed in “ohms”;
G is expressed in 1/ohms × cm; in modern instruments as “Siemens” (S).
Many factors influence the conductivity in your experiment; measuring
conductivity of a salt solution: the number of ions, their concentration, their
charge, their size, and ion mobility; therefore: |
|
- Conductivity is measured at a very low concentration (mM).
- Usually, a standard curve of that specific salt solution is generated, before
you determine the (unknown) concentration.
|
