The Benefits of Ultra-High-Performance Supercritical Fluid Chromatography in Determination of Lipophilic Vitamins in Dietary Supplements
Abstract
Nine tocopherol derivatives including four tocopherols, four tocotrienols, and one esterified form of -tocopherol acetate were analyzed using ultra-high-performance supercritical fluid chromatography (UHPSFC) with diode array detection. The separation was carried out on BEH 2-EP column using shallow gradient elution of 1-4% methanol and CO2 in 5min.
Complementary ultra-high-performance liquid chromatography method was developed using Ascentis Express F5 core-shell stationary phase and isocratic elution with 75% acetonitrile/methanol (1:1) and 25% water. This separation took 12min that is the shortest liquid chromatography run in analysis of all tocopherol derivatives reported so far.
However, our UHPSFC method resulted in more than two times faster analysis, and allowed direct injection of heptane solutions and extracts from liquid-liquid extraction. These features made UHPSFC a method of choice for subsequent analysis of dietary supplements containing different forms of vitamin E.
Sample preparation methods were optimized for individual dosage forms of drops, capsules, tablets, and granulate.