headspace samplerIt is to put the sample to be tested into a closed container, volatilize the volatile components from the sample matrix by heating and heating, reach equilibrium in the gas-liquid (or gas-solid) two phases, and directly extract the top gas for chromatographic analysis, so as to check the composition and content of the volatile components in the sample. The use of headspace sampling technology can avoid lengthy and complicated sample pretreatment process, avoid the interference of organic solvents on the analysis, reduce the pollution of the column and inlet. The instrument can be connected with various types of gas chromatograph at home and abroad.

Of course, headspace analysis can also be regarded as a gas phase extraction method, that is, gas is used as a solvent to extract the volatile components in the sample. Therefore, headspace analysis is an ideal sample purification method. traditional liquid-liquid extraction and SPE The sample is dissolved in the liquid, there will inevitably be some co-extract interference analysis, and the purity of the solvent itself is also a problem, which is particularly important in trace analysis, and gas as a solvent can avoid unnecessary interference, because high-purity gas is easily available, and the cost is low.

Headspace analysis methods include manual method, airtight needle injection method, balanced pressurization system, quantitative ring pressurization system and static-dynamic compensation type. Headspace gas chromatography analysis usually places the sample in a closed constant temperature system. When the gas-liquid (gas-solid) two phases reach thermodynamic equilibrium, sampling is taken and the gas phase composition is analyzed and determined by gas chromatography. The determination can be carried out in two ways, one is static method and the other is dynamic method. The static method is suitable for occasions where the sample is large, while the dynamic method is suitable for occasions where the sample volume is small or special.