The gas chromatograph injection system includes a sample introduction device and a vaporization chamber. To obtain good GC results, the sample is first quantified into the chromatographic system and the sample is effectively vaporized. Then use the carrier gas to quickly “sweep” the sample into the column. To this end, pay attention to the following technical indicators.

1 operating temperature range

General gas chromatography instruments have a maximum vaporization temperature of 350 to 420 °C and some can reach 450 °C. Technically, this temperature setting can be higher, but since the maximum operating temperature of the column does not exceed 400 °C, it is not necessary to design a higher vaporization temperature.

2 carrier gas pressure and flow setting range

The carrier gas pressure range of common instruments is 0~689.2kPa , and the flow range is between 0~200ml/min . When the EPC is configured , the pressure and flow range will be larger.

3 dead volume

The dead volume of the vaporization chamber should be small enough to ensure that the initial band of the sample entering the column is as narrow as possible, thereby reducing the extra-column effect. The dead volume of a common vaporization chamber is 0.2~1mL .

4 inert

The interior wall of the vaporization chamber should be sufficiently inert to adsorb or chemically react with the sample, and it cannot catalyze the decomposition of the sample.

5 septum purging function

Because the injection septum is typically made of a silicone rubber material, it inevitably contains some residual solvent and / or low molecular oligomers.