In order to observe the absorption of UV light by an analyte, silica gel which has been impregnated with a fluorescent material is used to prepare the TLC plate. Light with a wavelength of 254 nm is used to illuminate the plate and if the analyte absorbs UV light it can be seen as a black spot on a yellow background where it quenches the fluorescence of the background. This method of visualisation is used in many pharmacopoeial tests since most drugs possess chromophores. If a compound is naturally fluorescent, longer wavelength light at 365 nm may be used to visualise the plate. For example, the pharmacopoeial test for anthraquinones in aloes observes the fluorescence of these compounds under UV light at 365 nm.
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Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.