Separation of Chlorogenic Acids and Caffeine on a Diasfer-110-C10CN Stationary Phase

It is shown that a transition from traditional C18 (I) stationary phases with non-polar endcapping to the C10CN (II) phase, containing terminal polar groups, leads to a change in selectivity comparable to an increase in the activity of residual silanol groups in phases I. The effect was detected in the separation of isomeric monocaffeoylquinic acids. Two versions of the gradient mode are proposed using a Diasfer-110-C10CN column and water–acetonitrile components of the mobile phase acidified with H₃PO₄ for the separation of chlorogenic acids and caffeine in green coffee extracts from different manufacturers. It was shown that the proposed chromatographic method can also be used to determine trigonelline, the retention of which significantly increased in replacing phase I with phase II. The proposed method was used to differentiate the fruits of two types of coffee—Arabica and Robusta. It was found that the total amount of chlorogenic acids and caffeine is higher in Robusta coffee extracts.