Analysis of mono‐, di‐, and triglycerides by capillary supercritical fluid chromatography

Abstract

AbstractThe separation of mixed mono‐, di‐, and triglycerides by capillary supercritical fluid chromatography is described. The separations were performed at low operating temperatures, using a carbon dioxide mobile phase, a conventional flame ionization detector, and two different stationary phases, DB‐5 (95% dimethyl‐(5%)‐diphenylpolysiloxane) and DB‐225 (50% cyanopropyl‐methyl‐(50%)‐methylphenylpolysiloxane). Because the separations were performed at low operating temperatures, no thermal degradation of the glycerides was observed. Even under these mild operating conditions, trinervonin, a triglyceride having a molecular weight over 1100 amu, was readily eluted. When rapid pressure programming of the carbon dioxide mobile phase was employed, trinervonin was eluted in less than two minutes. On DB‐5, the mono‐, di‐, and triglycerides eluted in order of increasing molecular weight. A graph of t′r (on DB‐5) versus molecular weight is linear. When DB‐225 was used as the stationary phase, triglycerides eluted in the order of increasing unsaturation. Thus, the order of elution on DB‐225 was tristearin, triolein, trilinolein, and trilinolenin.