Basic structure of gas chromatograph

The basic structure of a gas chromatograph has two parts, an analysis unit and a display unit. The former mainly includes gas source and control metering device, sample introduction device, thermostat and column. The latter mainly consists of a calibrator and an automatic recorder. The column (including the stationary phase) and the calibrator are the core components of the gas chromatograph.

(1) The gas path in the gas chromatograph of the carrier gas system is a closed piping system in which the carrier gas continuously operates. The entire carrier gas system requires pure carrier gas, good airtightness, stable flow rate and accurate flow rate measurement.

(2) Injection system injection is the rapid and quantitative addition of gas or liquid sample to the upper end of the column.

(3) Separation system The core of the separation system is a column, which functions to separate multi-component samples into individual components. The column is divided into two types: packed column and capillary column.

(4) Detection system The function of the detector is to convert the sample components separated by the column into electrical signals according to their characteristics and contents, and after amplification, record them into a chromatogram by a recorder.

(5) Signal recording or microcomputer data processing system. In recent years, gas chromatographs mainly use chromatographic data processing machines. The chromatographic data processor prints the recorded chromatogram and prints the processed results on the same sheet of paper, such as retention time, mass fraction of the component being tested, and so on.

(6) The temperature control system is used to control and measure the temperature of the column, detector and gasification chamber, and is an important part of the gas chromatograph. Gas chromatographs fall into two categories: one is a gas-solid chromatograph and the other is a gas-liquid partition chromatograph. The stationary phases separated by these two types of chromatographs are different, but the structure of the instrument is universal.