Why isn't TLC typically appropriate for quantitative analyses?

Thin Layer Chromatography (TLC) is generally not suitable for quantitative analyses because it is primarily a qualitative technique that provides information about the presence and identity of compounds rather than their precise concentrations. The detection and measurement of spots on the TLC plate can be influenced by factors such as spot size, solvent front variations, and visual interpretation, leading to variability and lack of reproducibility. Additionally, TLC does not provide a direct correlation between the amount of substance and the intensity of the spot, making it challenging to derive quantitative results accurately.