What is the Difference Between Potentiometry and Amperometry?

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Potentiometry and amperometry are both electroanalytical methods used in analytical chemistry. The key difference between these two techniques lies in the parameters they measure and how they maintain constant conditions. Here is a comparison of the two methods:

Potentiometry:

  • Measures electric potential (or voltage) while maintaining a constant (normally nearly zero) electric current between the electrodes.
  • Commonly used to find the concentration of a solute in a solution.
  • Uses indicator electrodes made selectively sensitive to the ion of interest.
  • Passively measures the potential of a solution between two electrodes, affecting the solution very little in the process.

Amperometry:

  • Monitors electric current (amperes) while keeping the potential constant.
  • Used to detect the ions in a solution depending on electric current.
  • Measures the current produced during the reaction between the analyte and the electrode.
  • Typically used in oxygen monitors or oxygen cathodes, titrations such as redox, precipitation, and complexometric titrations.

In summary, potentiometry measures the electric potential while maintaining a constant electric current, while amperometry monitors the electric current while keeping the potential constant. Both methods are important analytical techniques in analytical chemistry.

Comparative Table: Potentiometry vs Amperometry

Potentiometry and amperometry are important analytical techniques in analytical chemistry. The key difference between them is that potentiometry measures the electric potential while maintaining a constant electric current, whereas amperometry monitors the electric current while keeping the potential constant. Here is a table summarizing the differences between potentiometry and amperometry:

Parameter Potentiometry Amperometry
Measured Parameter Electric Potential Electric Current
Electrode Configuration Constant current, normally nearly zero Constant potential
Applications Used in titrations and ion concentration determinations Used in chemical sensors and detecting analytes in flow systems
End-point Determination Yes, based on the potential change No, does not result in a voltage-vs-current plot (voltammogram)

Both potentiometry and amperometry have their advantages and are used in different applications in analytical chemistry.