中文摘要：

以1个常规六通阀直接连接两支常规尺寸的色谱柱（250mm×4．6mm i．d．），构建简单的SCX／RP在线二维液相色谱系统，对中成药六味地黄丸组分进行了优化分离。样品经过第一维阳离子交换色谱（HypersilSCX），洗脱产物分离后通过六通阀直接富集到反相分析柱（C18）顶端，被转移到第二维色谱柱上继续进行分离。经过11步不连续的线性梯度洗脱，二维分离系统出峰数量达到550多个，峰容量达到2266。构建的二维液相色谱系统结构简单，与一维色谱相比，具有分辨率高、峰容量大的特点。

英文摘要：

A simple on-line two-dimensional liquid chromatographic system was constructed using strong cation exchange chromatography （SCX） followed by reversed phase chromatography （RP） to analyse Chinese patent medicine Liuwei Dihuang Pills. A 2-position-6-port valve was used as a switch interface to connect two common size （250 mm × 4.6 mm i. d. ） columns. The experiment was carried out as follows： the sample, after the first dimensional cation exchange （ Hypersil SCX）, was enriched on the head of RP analytical column （ C18 ） through the 6-port valve ; By switching the valve, the fractions from the SCX were transferred to RP for further separate. Eluted by discontinuous 11 steps with increasing salt concentration, the system led to over 550 peaks, with the total peak capacity high up to 2266. Compared with one-dimensional chromatography, the system got large improvement in the resolution and total peak capacity. The sample which could not be separated in the one-dimensional model, but be separated well in the two-dimensional system.