... 1, after sweeping clean, switch V1 from OFF to ON, carrier gas 1 takes sample into analytical column ... components flowing out, switch valve 1 from OFF to ON, C6+ was flow back to TCD, examined. Components O2, N2, CH4, ... column 13X, switch the valve V3 from OFF to ON. Components CO2 and C2 will be detected ... TCD in sequence. Switch the valve V3 from ON to OFF, components O2, N2, CH4 and CO will ...