Electronic spectroscopy sample quantities required

The only way to overcome all of these problems is to use a nondestructive in situ analytical technique. Given the small quantities of colorants present in trace samples, ultaviolet (UV)-visible microspectrophotometry is one of the few analytical techniques that can be used in situ. Unfortunately, the electronic spectra data obtained provide only a very limited amount of molecular information to compare samples and help in the identification of a dye. The technique is very poor where discrimination of dyes in the mixture is required and this can be a key piece of information, for example, if a fiber is to be related to a garment. Thus, Raman spectroscopy using near-infrared excitation and SERRS are techniques with very considerable potential in forensic analysis. 

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