For the carbon dioxide measurements, Shimadzu GC-2010 gas
chromatograph equipped with a TCD and HP-PlotQ column
(30 m 0.53 i.d. 0.25 mm) was used. The temperature of the
injector and oven were 200 C and 90 C, respectively. Samples of
50 mL were injected via a split injection port at a split ratio of 0.5:1.
Carrier gas was nitrogen at a flow rate of 63.8 mL/min.