Instrumental methods differ from classical methods mainly in how the analysis is performed and the type of tools used.
Classical methods depend on chemical reactions such as precipitation, titration, or color change to measure the amount of a substance. They use simple laboratory tools like burettes, pipettes, balances, and glassware. These methods usually give approximate results and require more manual work and observation. They are slower, less sensitive, and need a larger amount of sample. Examples include titration, gravimetric analysis, and flame tests.
Instrumental methods, on the other hand, depend on physical properties such as light absorption, conductivity, mass, or emission of radiation. They use advanced instruments like spectrophotometers, chromatographs, and mass spectrometers. These methods are fast, highly sensitive, and provide accurate quantitative results. They often require very small samples and are mostly automated, reducing human error. Examples include UV-Visible spectroscopy, chromatography, and atomic absorption spectroscopy.
In simple terms, classical methods rely on chemical reactions and manual measurements, while instrumental methods use physical principles and modern instruments for faster, more precise, and automated analysis.