Retinol, cholecalciferol and alpha-tocopherol contents of Bulgarian Black Sea fish species

The aim of the present study is to determine and to compare the content of retinol, cholecalciferol and alpha-tocopherol in edible tissue of two Black sea fishes - Garfish (Belone belone) and Turbot (Psetta maxima). All-trans-retinol (vitamin A), cholecalciferol (vitamin D₃) and alpha-tocopherol (vitamin E) were analyzed simultaneously using HPLC/UV/FL system (Thermo Scientific Spectra SYSTEM) equipped with RP analytical column. The mobile phase was composed of 97:3 = MeOH:H2O. Retinol and cholecalciferol were monitored by UV detection at lmax = 325 nm and lmax = 265 nm, respectively. Alpha-tocopherol was detected by fluorescence at lex=288 nm and lem=332 nm. The sample preparation procedure includes alkaline saponification, followed by liquid-liquid extraction. Quantities of all-trans-retinol and cholecalciferol were higher in garfish tissues while alpha-tocopherol content in turbot showed seven times higher values.