| A gas chromatographic analysis technique with parallel detectors of flame ionization detector and thermal conductivity detector（GC-FID/TCD） was established.The method can be used to determine 16 gases（C1-C6 alkanes,CO2,H2S,O2+N2） of natural gas hydrates simultaneously by one injection.The analysis parameters,such as capillary column,temperature program,column flow,inlet temperature,detector temperature,the reference and makeup flow of TCD were optimized.Under the optimal conditions,good linearities were obtained in the experimental concentration range for the 16 gases with correlation coefficients（r2） of 0.999 03 – 0.999 98.The limits of detection ranged from 0.000 3 mol/mol to 0.046 mol/mol with relative standard deviations（RSDs,n=6） of 1.6%-5.0%.The method was successfully applied in the determinations of gas compositions in the natural gas hydrates from Qilian Mountain Permafrost,South China Sea and laboratory synthetic samples.The result showed that the method was simple,practical,sensitive and reliable,and was suitable for the determination of gases in natural gas hydrates. |