使色谱峰产生拖尾的一个因素--柱出口效应

使用塔板理论证明存在一种使正常色谱峰产生拖尾的因素－柱出口效应。证明符合线性分配的样品组分虽然在色谱内存在3种不同浓度的分布形态，但在流出色谱后却都因柱出口效应的影响而转变成拖尾峰。在不加任何近似处理的情况下，使用塔板理论直接对不同塔板数、容量因子的色谱峰不对称性进行了计算；计算结果同样支持了柱出口效应的存在。

A Factor for Causing Chromatographic Peak to Tail - -Effect of Column Outlet

A factor-effect of column outlet could cause normal chromatographic peak to tail when the solute left the end of the column was proved by plate theory. When the distribution coefficient was constant and independent of the amount of solute present in a plate, the distribution of solute could have three shapes in the column, but they all turned to skewed peaks when leaving the end of the column. The last plate makes the solute change their shape to skewness when they left the end of the column; this factor was named the "effect of column outlet". The asymmetry of solute inside or outside of the column was calculated by using dircetly plate theory under the different number of plate n and partition ratio k', A% = (Ab - Af)/(Ab + Af)12] (Ab = back area and Af = front area of the peak, measured from a vertival line through the base line), the A% proved to have the effect of column outlet again. The effect of column outlet could be eliminated with temperature program in gas chromatography and elution gradient in liquid chromatography, using these methods could reduce the k' in the last plate, therefore the near symmetrical peak could be obtained when use these methods.