[Simultaneous determination of chlorogenic acid and cynaroside contents in Lonicerae Japonica Flos by high resolution sampling two-dimensional liquid chromatography].

ABSTRACT

An innovative analytical method based on high resolution sampling two-dimensional liquid chromatography (HiRes 2D-LC) was established for determination of chlorogenic acid and cynaroside in Lonicerae Japonica Flos. A C18 column was used in the first dimension (1D)-LC separation with acetonitrile and 0.4% (v/v) phosphoric acid aqueous solution as mobile phases. Five heart cuts of chlorogenic acid and four heart cuts of cynaroside were stored in 2D-LC interface, which was a 5-position-10-port valve equipped with two multiple heart-cutting valves. The stored cuts were sequentially separated in the second dimension (2D)-LC. The 2D separation was carried out on an SB-Phenyl column with acetonitrile and 0.5% (v/v) acetic acid aqueous solution as mobile phases. The results showed that chlorogenic acid peaks in the 1D were well separated, whereas cynaroside peaks in the 1D were co-eluted with interferences. The above two targets were accurately quantified through a high resolution sampling mode based on continuous slice cuts of the whole target peaks. The method had good linearity, recovery and repeatability. The HiRes 2D-LC system could be used to improve separation and quantification of (un)targets in traditional Chinese medicine samples.