Ultraviolet, Visible, and Fluorescence Spectroscopy

Spectroscopy in the ultraviolet-visible (UV-Vis) range, the subject of this chapter, is one of the most commonly encountered laboratory techniques in food analysis. The analytical signal in such assays is based on either the emission or absorption of radiation in the UV-Vis range. This signal could be inherent in the analyte or a result of a chemical reaction involving the analyte. This chapter covers the following spectroscopy concepts: UV (200–359 nm) vs. Vis (350–700 nm) portions of the electromagnetic spectrum, absorbance vs. fluorescence, qualitative vs. quantitative analysis, components of a spectrophotometer, use of Beer’s law and a calibration curve to estimate the analyte concentration of a test solution. Quantitative absorption spectroscopy, the most common of the subdivisions within UV-Vis spectroscopy, is the basis of many techniques described in other chapters.