Potentiometry

Fundamentals of Potentiometry

• theoretical basis of potentiometric analysis; the dependence of electrode potential on analyte concentration. Definition of a Nernstian electrode.
• uses and advantages of potentiometric analysis
• practical reference electrodes: ideal characteristics and some common reference electrodes
• factors affecting measured cell potentials of galvanic cells. Reasons to minimize current flow in potential measurements. Description of iR drop.
• origin of junction potentials. Salt bridges.
• electrode polarization in galvanic cells: effect and explanation. Definition of overpotential.

Metal Indicator Electrodes

• metal electrodes of the first kind. The most useful metal electrodes.
• metal electrodes of the second kind and how they work
• inert electrodes (metal and nonmetal)

Membrane (Ion Selective) Electrodes

• problems with metal indicator electrodes
• general description of ISEs and their response to analyte concentration.
• categories of ISEs
• glass ISEs; the pH electrode
• crystalline ISEs. The fluoride ISE, and ISEs based on membranes of silver salts. "First-" and "second-order" Ag ISEs.
• liquid ISEs. Description of calcium ISE.

Methodology and Characteristics of Potentiometric Methods

• the need for ionic strength buffers
• sources of error in potentiometric measurements; factors ultimately limiting the precision
• advantages/disadvantages of potentiometric methods