Method for separating diastereomers of pristane

A method for separating diastereomers of pristane in isoprenoid hydrocarbons, comprising:

• preparing a pristane standard sample with a concentration of 0.05 mg/mL;
• and
• injecting the pristane standard sample into an Agilent 7890 gas chromatograph equipped with a 7000B triple quadrupole mass spectrometer for GC/MS/MS analysis;
• wherein an injection volume is 2 μL;
• a chromatographic column is a 30 m×0.32 mm×0.25 μm Rt-βDEXcst chiral chromatographic column;
• individual components in the pristane standard sample are identified according to a characteristic ion and relative retention time of a corresponding reference standard and search results in NIST 11 library;
• a blank sample is injected between two adjacent injections of samples;
• chromatographic conditions are listed as follows:
• a carrier gas of the Agilent 7890 gas chromatograph is helium with a constant flow rate of 0.8 mL/min;
• a temperature of an injection port is 280° C.;
• and a heating program of the Rt-βDEXcst chiral chromatographic column is set as follows:
• initial temperature 100° C. for 5 min;
• rising to 120° C. at 1° C./min;
• and 120° C. for 20 min;
• and
• mass spectrometry conditions are listed as follows:
• an ionization energy is 70 eV;
• an ion source temperature is 230° C.;
• and
• collection mode:
• full scan (SCAN) and multiple reaction monitoring (MRM);
• and a scanning mass range:
• 80-300 amu.