The invention provides a method for detecting primary metabolites and secondary metabolites in fresh tobacco leaves with GC-MS (
gas chromatography-
mass spectrometer). The method comprises steps as follows: the fresh tobacco leaves are rapidly collected and quick-frozen with
liquid nitrogen on site, the quick-frozen tobacco leaves are transferred to
dry ice and transported to a laboratory at low temperature,
moisture is removed by a freeze dryer with a low-temperature
freeze drying method, the tobacco leaves are pulverized by a
pulverizer and screened by a 40-mesh
sieve, the primary metabolites and the secondary metabolites of the pulverized tobacco leaves are extracted ultrasonically with a
solvent, a supernatant of an extracting solution is subjected to
nitrogen blow-
drying, blow-dried extracts are subjected to an oximation reaction and a
silane derivatization reaction, and GC-
MS analysis is performed finally. The method has the advantages as follows: a
tobacco leaf collecting method can really reflect growth and development periods, collecting parts, varieties and production places of the tobacco leaves; a
tobacco leaf extracting and detecting method can cover the primary and secondary metabolites such as
sugar,
amino acid,
organic acid,
sterol,
alkaloid,
polyphenol and the like of the fresh tobacco leaves and has high-flux detection characteristics, and a selective
ion monitoring method can realize accurately qualitative and quantitative analysis of 199 primary and secondary metabolites in the fresh tobacco leaves, and 135 metabolites are required to be verified in a standard substance.