Gas chromatograph (GC) and the principle

Detectors of Gas chromatograph

Table 1　Detectors of Gas chromatograph

Introduction of sample to GC

• Direct injection of solvent or gas
• HS (headspace) method

Liquid or solid sample is placed in a vial, sealed and heated. Gas phase is collected and injected.

• Pyrolysis method

Sample is injected after heat extraction or pyrolysis (of polymers and high boiling substances).

• Heat desorption method

Liquid samples based on Stir Bar Sorptive Extraction (SBSE), gas concentrated using TENAX sorbent tube, or solid samples are heated.

After concentrating the gas phase in the cooling trap,  injected by heating and desorbing.

Injecting a sample into GC requires not merely introducing a gas or a solvent in which the sample is dissolved, but also selecting a suitable pretreatment method according to the application.

Table 2　Pretreatment methods of GC