| An on-line two-dimensional liquid chromatography (NPLC×RPLC) was developed. Normal-phase liquid chromatography (NPLC) with an Hypersil SiO2 column was used as the first dimention, and reverse-phase liquid chromatography (RPLC) with a Kromasil C18 column was used as the second dimention, the interface was based on a ten-port, two positon valve with a 200μL sample loop. The incompatability of the two dimentional moble phases was avoided because of the use of reduction the sample-loop volume, and the mixture of 1,4-dioxane and n-hexane used as NPLC mobile phase. The elevation of column temprature can improve the compatability of the two dimentional mobile phases and increase analytical speed. The Zhengtian Wan was seperated in this 2D-LC system, 733 chromatography peaks were detected, the total system peak capacity was 1470. In order to increase the peak capacity of this system, two Kromasil C18 columns in series were applied in the RPLC to analyze Zhengtian Wan, 876 chromatography peaks were achieved, the peak capacity was 1740. The established 2D-LC and applied strategy offered a novel idea for the mobile phase choice of multi-dimensional separation. |
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