The accumulated gases in the syringe were identified by gas chromatography
using 100/120 Carbosieve S-II. Helium gas flowing at 30 ml min−1 was
used a carrier gas, and the temperatures of injector and thermal conductivity
detector were 100 and 150°C, respectively. The column temperature was 35°C at
the beginning, and increased from 35 to 70°C at a rate of 8°C min−1 after 7
min.