全二维液相色谱(NPLC×RPLC)接口及其应用

Sample Loops-valve Interface of Comprehensive Two-dimensional Liquid Chromatography(NPLC×RPLC) and Its Application

用内径为0.53mm的填充毛细管正相液相色谱为第一维,用4.6mm(i.d.)×50mmRP-18e整体柱反相色谱为第二维,建立了定量环-阀切换接口的全二维液相色谱系统(NPLC×RPLC).第一维色谱分离洗脱出的组分交替存储在十通阀上的两个定量环中,同时定量环中前一个组分被转移到第二维进行反相分离.因为第一维的流动相流量仅是第二维的1/500,自然解决了流动相兼容问题.采用芳香族化合物的混合物和中药丹参正己烷提取液对该全二维液相系统的分离能力进行了评价.

A comprehensive two-dimensional liquid chromatography（NPLC × RPLC） was developed. Normal phase liquid chromatography（NPLC） with a CN microcolumn was used as the first dimension, and reversedphase liquid chromatography （RPLC） with a monolithic column was used as the second dimension. The interface was based on a ten-port, two-position valve with two storage loops. The first column was operated at a flow rate of 8 uL/min in isocratic mode, while the monolithic column flow rate was 4 mL/min and was operated in gradient mode. The sample loops had a volume of 12 uL each, and the analysis time in the second dimension was 1.5 min. The primary fractions were stored into the two storage loops alternately, and then were separated by the secondary column sequentially. AUV detector was used after the secondary column. The use of a monolithic column in the second dimension permits a very fast analysis operating at bighter flow rates without loss of resolution, since the monolithic column has higher permeability than conventional packed columns. The incompatibility of the two dimensional mobile phases was avoided because the flow rate of the first dimension is only 1/500 of that of the second dimension. The performance of the system was evaluated by several standards mixture and Radix salviae miltiorrhiza bage extract and the advantage of using 2D-LC over one-dimensional chromatographic techniques is clearly demonstrated in the analvsis of the extract.