Amperometry is an electrochemical technique where the current is measured at a fixed potential over time to study the concentration of an analyte. It is widely used in sensors, biosensors, and analytical chemistry. Here’s a clear explanation:
1. Setup
- Working electrode: Where the oxidation or reduction of the analyte occurs.
- Reference electrode: Maintains a stable potential.
- Counter electrode: Completes the circuit.
- Electrolyte solution: Contains the analyte to be measured.
2. How it works
- A fixed potential is applied to the working electrode, chosen so that only the target analyte undergoes oxidation or reduction.
- The analyte reacts at the electrode surface, producing electrons, which generate a current.
- This current is proportional to the concentration of the analyte in the solution.
- By recording the current over time, changes in analyte concentration can be monitored.
3. Key Points
- The current depends on diffusion of the analyte to the electrode surface.
- Amperometry is very sensitive and can detect low concentrations.
- It is widely used in glucose sensors, environmental monitoring, and drug analysis.
4. Example
- In a glucose biosensor, glucose is oxidized at the electrode surface, generating a current. The magnitude of this current indicates the glucose concentration in blood.
In simple words: Amperometry measures how fast electrons flow when a specific reaction happens at a fixed voltage, which tells us the amount of a chemical present.