The analysis method of the purging device is to inject inert gas into the liquid sample (or solid surface), blow out the components to be analyzed, concentrate into the adsorber through the container of the adsorbent, then heat the adsorbent to separate the adsorbed components, and introduce the gas phase column with carrier gas for analysis. The dynamic headspace analysis method has rich functions and is beneficial to the analysis of trace components. The main problem is that it takes a long time, impurities may be introduced during the cleaning process, and the performance of the adsorbent is selected.

The analytical steps of gas chromatography are as follows:

① Add a certain number of samples into the purge bottle;

After drying and purifying by silica gel, molecular sieve and activated carbon, the gas cylinder is purged by a certain circulation to remove volatile components;

③ Retain the stripping components in the adsorbent or cold trap;

④ Open the six-way valve and place the adsorption tube in the GC analysis flow channel;

⑤ heating adsorption tube desorption, blowing volatile components into the human body analysis column;

The use of chromatographic analysis.

Technical points of each step:

① According to the experimental needs to choose different specifications of the automatic sampling device: sampling volume, solid liquid automatic identification, weighing and other functions.

Whether purification needs heating: infrared heating.

③ Inert treatment of transmission pipeline.

The adsorption should be in a low temperature environment, desorption should be heated immediately. Because the low temperature environment depends on air cooling, jacket heating affects air cooling, and direct heating wire heating. Heat up as quickly as possible.

⑤ Due to the instantaneous heating, gas expansion and moisture blown out in the previous step, cold focusing is required to eliminate moisture. Using micro-adsorption technology, the carrier gas flow rate is reduced to 1-5 ml/min, and it can directly enter the GC without splitting.

The process of sweeping and collecting method is to use nitrogen, helium or other inert gases to purge in liquid or solid, blow out the trace volatile components to be analyzed, and then be adsorbed by the adsorbent in the cold trap, heated and desorbed, and enter the gas chromatography system for analysis. In a closed container, volatile components are continuously passed from the liquid phase into the gas phase and blown away as the purging of the gas disrupts the equilibrium of the gas and liquid phases. That is, any component at the top of the liquid phase will be dispersed to zero, so that more volatile components can be released from the gas phase. Therefore, the purge and trap method is lower in trace content than the static top.