Which method is considered the classical method of analysis?

The classical method of analysis referred to in this context is gravimetric analysis. This method is based on the measurement of mass and relies on the precise weighing of an analyte. Gravimetric analysis involves the conversion of a sample into a stable and pure product that can be accurately weighed. This technique is valued for its precision and accuracy, making it a fundamental part of analytical chemistry.

Gravimetric analysis includes steps such as precipitation, filtration, and drying or igniting the precipitate to achieve a pure compound, where the mass of the compound directly correlates to the amount of analyte present in the sample. It is one of the oldest quantitative analytical methods and serves as a benchmark for the accuracy of other newer methods.

In contrast, spectrophotometry and chromatography are more contemporary techniques that involve measuring the interaction of light with a sample or separating mixtures, respectively. While titration is also a widely-used method in analytical chemistry, involving the addition of a reagent to a solution to determine its concentration, it is typically viewed as a volumetric analysis rather than a classical gravimetric analysis. Gravimetric methods provide fundamental principles that can be applied across various areas of analytical chemistry, reinforcing their classification as classical methods.