High performance reversed phase chromatography of natural triglyceride mixtures: critical pair separation [Chemical analysis of vegetable oils]

The separation of the critical triglyceride pairs C48:0, C50:l, C54:3ccc and C54:3ttt as well as C54:2, C52:l and C50:l has been accomplished without the aid of any interacting ion such as silver. A theoretical carbon number (TCN) for the unsaturated triglycer‐ides can be calculated from the carbon number (CN) and capacity factor (k’) relationship of the saturated triglycerides, and used to predict the separation of critical pairs. A mathematical equation was derived for the identification of not only the triglycerides by their carbon number and number of double bonds but also the possible acyl groups present in these triglycerides. The pattern of triglyceride elution sequence within each triglyceride category with the same equivalent carbon number (ECN) starts with the triglyceride with the highest number of double bonds and terminates with those with the lowest number of double bonds, with the lower ECN triglycer‐ides eluting ahead of those with higher ECN. A possible mechanism for the separation of these triglycerides on highly efficient columns packed with 5n silica bonded with the octadecyl stationary phase is postulated.