Gas chromatography was performed on Shimadzu
17 A with a DB-wax fused silica capillary column (30m x
0.25 mm id., 0.25 mm film thickness). The injector
temperature and flame ionization detector were maintained
at 250 oC. The column temperature program was started
at 150 oC and held for 1 min, then ramped to 180 oC with a
heating rate of 25 oC/min and a final temperature was
increased to 200 oC at a rate of 2 oC/min and held for 10
min. The pressure of the nitrogen carrier gas was 100
kPa.