Application of micellar electrokinetic chromatography (MEKC) to the quantitation of nutraceuticals in Citrus fruits

Citrus fruits (e.g., oranges, lemons) are among the most consumed fruits worldwide, and are a considered a reliable and easily accessed source of essential nutrients (such as vitamins). They are also rich in other health-promoting substances, such as adrenergic amines, polyphenols and coumarins and, for this reason, they can be considered "nutraceuticals" in every respect. However, the information available on these latter compounds is still insufficient, particularly regarding their content in the different kinds Citrus fruits. The aim of this study is the development of an original micellar electrokinetic chromatographic (MEKC) method for the analysis of some nutraceutical compounds (catechins, coumarins, glycosidic flavanones) in Citrus fruits (such as grapefruit, lime, pomelo and citron). The method uses a BGE containing SDS and β-cyclodextrin in borate buffer, a 48.5-cm uncoated fused silica capillary and a photodiode array (PDA) detector set at 205 nm; the analytes are extracted from the fruit samples by pre-treatment with solvent followed by a solid-phase extraction (SPE) procedure. The method performance achieved until now is satisfactory in terms of rapidity, feasibility, reliability and the application to several kinds of Citrus fruits and derivatives is currently under way.