Here are the main limitations of gravimetric analysis, explained:
- Time-consuming process
- Gravimetric analysis involves several steps — precipitation, filtration, washing, drying, and weighing — which take a long time to complete.
- Requires high purity
- The precipitate must be very pure and completely dry to get accurate results. Even small impurities can cause large errors in weight.
- Needs careful handling
- Any loss of the sample during filtration, washing, or transfer can lead to incorrect results. It requires skilled handling and precision.
- Not suitable for trace analysis
- When the amount of the substance to be measured is very small, the change in mass may be too tiny to measure accurately.
- Interference by other ions
- Other substances in the sample may form similar precipitates or react with reagents, causing contamination and inaccurate results.
- Requires stable compounds
- The final compound formed for weighing must be chemically stable (not volatile or hygroscopic). If it absorbs moisture or decomposes, errors occur.
- Limited to certain elements
- Gravimetric methods work best for substances that can form insoluble, weighable compounds. Some elements or compounds cannot be analyzed easily this way.
- Equipment sensitivity
- Requires very sensitive analytical balances and controlled environmental conditions (temperature, humidity) for precise weighing.
In short, gravimetric analysis is accurate and reliable but slow, delicate, and not practical for all types of samples or very small quantities.