Carbon-based ultraviolet absorbance

Spectroscopy is a technique for analyzing the stmcture of molecules, usually based on differences in how they absorb electromagnetic radiation. Although there are many types of spectroscopy, four are used most often in organic chemistry (1) nuclear magnetic resonance (NMR) spectroscopy (2) infrared (IR) spectroscopy (3) ultraviolet (UV) spectroscopy and (based on a different principle) (4) mass spectrometry (MS). The first, NMR spectroscopy, probes the stmcture in the vicinity of individual nuclei, particularly hydrogens and carbons, and provides the most detailed information regarding the atomic connectivity of a molecule. 

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