How can separated spots on a TLC plate be visualized?

The correct choice is to use UV light or specific staining reagents for visualizing separated spots on a TLC (Thin Layer Chromatography) plate. TLC is a technique used to separate non-volatile mixtures, and the visualization of the spots after separation is critical in analyzing the components.

When UV light is applied, many organic compounds exhibit fluorescence or will absorb UV light, allowing them to appear as dark spots against a bright background on the TLC plate. This method is particularly useful for compounds that are not colored and may not be visible to the naked eye. In addition, staining reagents can be used after the development of the TLC plate. These reagents react with specific types of compounds and change color, making the spots visible. Different staining methods can be employed based on the nature of the compounds being analyzed.

Using heating to visualize spots does not provide reliable results as it may not enhance visibility for most organic compounds on the TLC plate. Looking at the colors alone may not yield accurate identification, especially for colorless substances. Adding more solvent after the spots have been developed does not aid in visualization; instead, it could cause the separation to blur or change, making it difficult to assess the original separation.

Hence, utilizing UV light or specific staining reagents