System and method for analyzing light n-alkane components and carbon isotopes in deep and ultra-deep source rock

A system for analyzing light n-alkane components and carbon isotopes in deep and ultra-deep source rocks, comprising:

• a source rock pyrolysis device;
• and
• a column box equipped with a programmable heating system;
• wherein the column box is provided with a 5A molecular sieve column, a dividing plate, a first chromatographic column, and a second chromatographic column;
• the pyrolysis device is connected to an inlet of the 5A molecular sieve column, and an outlet of the 5A molecular sieve column is connected with an inlet of the dividing plate;
• a first outlet of the dividing plate is connected with the first chromatographic column through a first pipeline, and a second outlet of the dividing plate is connected with the second chromatographic column through a second pipeline;
• and the first outlet of the dividing plate is provided with a first valve, and the second outlet of the dividing plate is provided with a second valve;
• the first chromatographic column is an empty column or a weak polarity column;
• and
• an outlet of the second chromatographic column is connected to a mass spectrometer.