WATERS液相色谱教程三四七(最全).ppt

* * * * * * * * * This is the outline of the seminar. In the introduction we will talk about our commitment to continued improvement of the quality and reproducibility of chromatographic columns and about the approach that we have taken. We will then talk about specifics: peak symmetry, why it is important and what improvements have been made; the results of our column stability studies; the important topic of column reproducibility. We will discuss the differences between column-to-column and batch-to-batch reproducibility, Waters Certificate of Analysis and our Method Validation Kit. We will then show selected application examples of the new Symmetry family of packings * To quantify tailing, I will be using the USP tailing factor, calculated as the ratio of the peak width to two times the width of the front half of the peak. The width measurements are made at 5 % of the maximum peak height. A perfectly symmetric peak has a tailing factor of 1. 当拖尾现象不太严重时（Tf或As＜1.5),两者基本相等;当拖尾现象比较严重时,As值要高于Tf值.重要的是,始终用一种方法来测定和比较. * With Symmetry columns, less mobile phase modifiers are required for basic compounds. Therefore, a simpler mobile phase is required. As a result, method transfer is easier. * With a tailing peak, defining how the baseline is drawn can be difficult. Drawing the baseline differently will result in different area/height values. This will reduce both the accuracy and precision of quantitation. With a symmetrical peak, determining baseline is straight-forward. Therefore, you get more consistent peak area which means more precise and accurate quantitation. * This example accentuates this concept. When high sensitivity applications are being used, the column can contribute to sensitivity performance of the method. The sample loaded onto the columns was equivalent for the column dimensions. Symmetry injection 10 uL and Zorbax injection 14 uL to compensate for column volume. At these low concentrations, the increased tailing reduced the peak height by almost