Electrochemical techniques are powerful tools for studying chemical reactions and detecting substances, but they also have several limitations. Here are the main ones explained:
1. Sensitivity to Impurities
- Even small amounts of impurities in the sample or electrolyte can affect measurements.
- Contaminants can cause unwanted reactions or distort current and potential readings.
2. Electrode Surface Issues
- The condition of the electrode surface is critical.
- Over time, electrodes can become fouled, oxidized, or damaged, reducing accuracy and reproducibility.
3. Limited to Electroactive Species
- Only compounds that can undergo oxidation or reduction (electron transfer) can be studied.
- Non-electroactive species cannot be analyzed directly.
4. Complex Data Interpretation
- Electrochemical signals often overlap when multiple reactions occur.
- It can be difficult to separate and interpret individual processes.
5. Requirement for Controlled Conditions
- Experiments need strict control of temperature, pH, and ionic strength.
- Small variations can cause large changes in results.
6. Reference Electrode Problems
- Reference electrodes can drift or leak, affecting potential measurements.
- Calibration and maintenance are essential but can be time-consuming.
7. Slow Reactions and Kinetic Limitations
- Some redox reactions are very slow or have high activation energies, making them hard to measure accurately.
- Mass transport limitations (diffusion) can also affect current responses.
8. Limited Selectivity
- Similar electroactive species may produce similar voltammetric peaks or currents, making it difficult to distinguish between them without additional techniques.
9. Instrumentation and Setup Complexity
- Requires precise instruments, high-purity chemicals, and proper cell design.
- Experimental setup errors can easily lead to inaccurate data.
10. Surface Reproducibility
- Reproducing exactly the same electrode surface condition for repeated experiments is challenging, leading to inconsistent results.