The flow rate of helium as carrier gas was 1.0 mL min1.
The oven temperature program began at 60C, was raised to 100C at H.-I. Kang, H.-S. Shin / Analytica Chimica Acta 852 (2014) 168–173 1691C min1, and then increased to the final temperature of 260C at25C min1 (held for 5 min).