How Do Locating Agents Work Under UV Light?

Points on working of locating agents under UV light are:

• Some locating agents produce fluorescence or quenching effects when exposed to ultraviolet light, making separated spots visible on the chromatographic medium. 
• This visibility occurs because the locating agent alters the way analytes absorb or emit UV radiation at their separated positions. 
• As a result, compounds that are otherwise invisible can be clearly detected without disturbing their location.

Also get more details on definition of locating agents in chromatography so check it out.