A New Method for Determination of α-Tocopherol in Tropical Fruits by Ultra Performance Convergence Chromatography with Diode Array Detector

A new method for the analysis of alpha-tocopherol in tropical fruits by ultra performance convergence chromatography (UPC2) was developed for the first time. Five varieties of tropical fruit samples were separately saponified under classical heating and extracted with ether. The extracted alpha-tocopherol was separated on a BEH column, with a mobile phase consisting of CO2 and methanol, with a gradient elution (99:1 to 90:10), and detected with diode array detector at 293 nm. The limit of detection (LOD) and limit of quantification (LOQ) were about 60.0 and 103.3 ng, respectively. This method was considered to be simple, fast and reliable, and successfully applied to analysis of alpha-tocopherol in tropical fruits. The values of alpha-tocopherol in pitaya, jackfruit, durians, mango, and papaya ranged from 0.16 to 0.45 mg/100 g dry weight in edible portion. Recovery rates obtained by the standard addition method on these tropical fruit samples ranged from 95.4 to 101.4 % with high repeatability (RSD, 1.2-2.6 %).