Abstract: One aspect of a GC analysis method according to the present invention is a GC analysis method for detecting a component contained in a sample gas by separating the component in a column, the GC analysis method including: a sample collection step (S1-S3) of collecting a sample gas from a solution containing an n-alkane, which is a reference compound of a retention index, by using a headspace method; a reference compound analysis step (S3) of introducing the sample gas collected in the sample collection step into the column and performing GC analysis; and a retention time calculation step (S4-S5) of obtaining an actually-measured retention time for the n-alkane on the basis of a chromatogram obtained by the GC analysis, and estimating a retention time of a compound to be analyzed from the actually-measured retention time and a known retention index of the compound to be analyzed.

Abstract: In gas chromatographic analysis, the consumption of a sample and the consumption of a carrier gas are reduced. In a direct injection unit (8), a small-capacity syringe (11) having a volume that exceeds 0 ?l and is less than or equal to 0.5 ?l , and a small-capacity insert (7) having a volume that exceeds 0 ml and is less than or equal to 0.4 ml are used. Besides, in a split injection unit (28), a small-capacity syringe (11) having a volume that exceeds 0 ?l and is less than or equal to 0.5 ?l and a small-capacity insert (7) having a volume that exceeds 0 ml and is less than or equal to 0.4 ml are used, and the split ratio during analysis is less than or equal to 3.