隔垫吹扫气流量对气相色谱分流/不分流进样口的影响简析

A Brief Discussion about the Septum Purge Flow's Influence on the Gas Chromatography Results based on the Split/Splitless Inlet

基于分流/不分流进样口,考察了隔垫吹扫气流量对几种常见样品气相色谱分离分析的影响。证明在分流模式下,隔垫吹扫气流量对色谱峰面积的影响要明显小于其在不分流模式下的影响。本实验证明,相对于不分流模式,10:1的分流比可以降低较大隔垫吹扫气流量所造成的峰面积损失。对于沸点差异较大的混合样品,同样大小的隔垫吹扫气流量会对高沸点样品的分析产生更大影响。其中在不分流模式下,30毫升的隔垫吹扫气流量甚至可以造成正四十四烷高达20%的峰面积流失。对于常见的苯系有机挥发物样品而言,如果进样量较大,导致其爆炸体积接近或超过衬管容量,则随着隔垫吹扫气流量增大到一定程度后,色谱峰面积的损失也将趋于稳定。

Based on the split/splitless inlet, the effect of the septum purge flow on the gas chromatograph results of several common samples was studied. It is proved that in the split mode the influence of the septum purge flow on the peak area is obviously smaller than in the splitless mode. Thereinto, the effect that the big septum purge flow shows on the peak area loss reduced clearly in the split ratio 10：1 mode, comparing with the splitless mode. On the other hand, considering the mixture samples with large variance of the boiling point, the same septum purge flow has bigger effect on the high boilers. In the splitless mode, the peak area of the tetratetracontane could reduce 20% by the 30 mL septum purge flow. For the BTEXs, if the inject volume is big enough and the explode volume is close to or exceed the liner capacity, the loss of the peak area will be stable when the septum purge flow increase and reach a high level