Quantitative analysis of flavonols, flavones, and flavanones in fruits, vegetables and beverages by high-performance liquid chromatography with photo-diode array and mass spectrometric detection.

A high-performance liquid chromatographic (HPLC) separation method with photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages. The compounds were analysed as aglycones, obtained after acid hydrolysis of freeze-dried food material. Identification was based on retention time, UV and mass spectra by comparison with commercial standards, and the UV peak areas were used for quantitation of the flavonoid contents. Examples of HPLC-MS, analyses of orange pulp, tomato, and apple are presented. The method has been used to screen foods on the Danish market, and the contents of flavones, flavonols, and flavanones were measured.