... 1 takes sample into analytical column DC200, before components flowing out, switch valve 1 from OFF to ON, C6+ was flow back ... when components H2S, C3 and above have not flowed out, switch the valve V2 from OFF to ON. Then H2S, C3 and ... CO2 and C2 flowing out, O2, N2, CH4, CO flow into chromatographic column 13X, switch the valve V3 from OFF to ON ...