Comprehensive Two-Dimensional Gas Chromatograph And Modulation Method

A modulation method using a comprehensive two-dimensional gas chromatograph, comprising the following steps:

• Step 1. Flow path connections:
• connecting an inlet end of a sample injector to a carrier gas line and an outlet end thereof to a first end of a primary dimension column;
• connecting a second end of the primary dimension column to a first branch of a three-way tube;
• connecting a second branch of the three way tube to a first end of a secondary dimension column;
• connecting a second end of the secondary dimension column to a detector;
• connecting a third branch of the three-way tube to a gas inlet of a two-position three-way valve;
• and connecting a first gas outlet of the two-position three-way valve to the carrier gas line, wherein the entireties of the primary dimension column and the secondary dimension column as well as part of the three-way tube are arranged inside a heating oven, and the two-position three-way valve is arranged outside the heating oven;
• Step 2. Controlling the two-position three-way valve such that the gas inlet of the two-position three-way valve is in communication with a second gas outlet other than the first gas outlet for a first predetermined time tfill during which the sample after primary dimension separation flows into the third branch of the three-way tube with the carrier gas;
• Step 3. After the end of Step 2, controlling the two-position three-way valve such that the gas inlet of the two-position three-way valve is in communication with the first gas outlet other than the second gas outlet for a second predetermined time tflush during which the carrier gas comes in from the first gas outlet and carries the sample present in the third branch of the three-way tube into the secondary dimension column for orthogonal separation.