Improving the Repeatability of Aqueous Solution Analysis Performed with Capillary Columns

Introduction

Sometimes it is difficult to attain a high level of repeatability when performing the split analysis of an aqueous sample with a capillary column. This is mainly because of the following factors: Because water has a high latent heat of vaporization, instantaneous vaporization in the sample injection chamber does not take place properly and the behavior at the split point is unstable. Because the vaporization volume is large, the volume of sample vapor exceeds the capacity of the glass insert. With split analysis, because the sample passes through the glass insert relatively quickly, sufficient vaporization is not possible if heat is not exchanged efficiently. In order to perform analysis with a high level of repeatability, it is necessary to insert silica wool in the glass insert to increase the heat capacity and thereby increase the vaporization efficiency. The silica wool not only increases the heat capacity, it also helps evenly mix the vaporized sample and is indispensable for split analysis.

February 27, 2007 GMT