超临界流体色谱系统中采用单泵在线添加改性剂

Single Pump On Line Addition of Modifier for Supercritical Fluid Chromatography

采用单个注射泵，以并联流路装置，在超临界ＣＯ２流体中在线添加甲醇等改性剂，用作填充柱超临界流体色谱的流动相。改性剂的粘度及流路长度显著地影响改性剂体积分数。利用该装置，可以方便地调节流动相的体积分数，改性剂的体积分数稳定且持久，可初步代替双注射泵系统添加改性剂。

Modified CO 2 as mobile phase is usually necessary for packed column supercritical fluid chromatography. Single syringe pump was applied in this work to add modifier through a parallel connection device, which can maintain constant and stable volume fraction of modifier without any contamination of the pump. Viscosity of the modifiers (here are methanol and acetone)and the length of the CO 2 pipe line/modifier pipe line can affect the volume fraction. Volume fractions of methanol and acetone were determined by gas chromatography and ultraviolet spectrometry respectively and their rules of variation were also examined. It shows that the volume fraction of methanol is lower than that of acetone under similar condition. With fixed modifierr line, the longer the CO 2 line is, the higher the volume fraction will be. The new device can conveniently alter the nature and ratio of the modifier with quite stable volume fraction. The online addition device can tentatively replace the dual pump system.