Flavonoids are a group of polyphenolic compounds present ubiquitously in plants. Flavanones are a class of flavonoids, present abundantly in Citrus species. In recent years, flavonoids have received greater attention by different researchers from multidisciplines such as plant biology, phytochemistry, agricultural scientists, and medical scientists. Biological activities of flavonoids specifically their role in plants as well as antioxidant activity, health-promoting properties, and modulation of plant-predator/pathogen interactions have been investigated. However, in order to investigate the biological activities and establish their physiological relevance, it is necessary to develop analytical tools to accurately determine the levels of the flavonoids in various tissues and matrices such as fruit, blood, and plasma. To facilitate such measurement, analytical tools to measure flavonoids were developed throughout the history of flavonoid research. In the present chapter, various tools such as thin-layer chromatography, high performance liquid chromatography, mass spectroscopy, and NMR used in analysis of flavonoids are discussed. In addition, the relevance and application of such tools in the analysis of flavanones, with emphasis on citrus flavanones, is discussed. 2012 John Wiley & Sons, Ltd.
