Ultraviolet–Visible and Fluorescence Spectroscopy

This chapter discusses ultraviolet–visible (UV-Vis) spectroscopy and fluorescence spectroscopy and their use in forensic science. UV-Vis spectroscopy analyses the electronic transitions that occur when the electromagnetic radiation incident on a sample is in the range 200–750 nm, i.e. the UV-Vis range. One of the more recent developments in UV-Vis spectroscopy and fluorescence spectroscopy is the use of hyperspectral imaging. Filtered light examination is a method of analysis that uses UV-Vis excitation to view forensic evidence. The chapter describes two types of coloured evidence, inks and fibres, routinely analysed using UV-Vis radiation source methods. In a forensic context, depending on the examination underway, interpretation for most spectroscopic techniques can be carried out on two levels: structural elucidation or comparison of spectra. Many of the principles of interpretation in UV-Vis spectroscopy can also be applied to fluorescence spectroscopy.