CHAPTER 11. Quantification and Method Validation

Abstract

To obtain reliable results, a method of analysis of naturally occurring carotenoids should include several steps (i.e. sampling and sample preparation, extraction, separation, identification and quantification, as well as validation of the chosen method). There is no official procedure or protocol for sampling and sample preparation with the purpose of obtaining a representative sample at laboratory scale. Despite the existence of other quantitative techniques (e.g. internal standard and standard addition methods), the carotenoids, including those acylated with fatty acids, are mainly quantified by liquid chromatography–diode array detectors, and their concentrations are estimated based on external calibration curves of free xanthophylls. The following performance characteristics have been the most applied for validation of a method for carotenoid quantification: accuracy, precision, limit of detection and limit of quantification. This chapter provides an overview of the current strategies used for food sampling and for the quantification of carotenoid esters, as well as of the validation of methods used in the quantitative determination of such compounds.