Table 1: Thermal desorption (TD)-GC-MS conditions.

TD parameters
 TD modelGerstel thermal desorption system (TDS)/cooled injection system (CIS)
 1st desorption temperature (°C)300
 1st desorption holding time (min)5
 1st desorption flow rate (mL/min)80
 Transfer line temperature (°C)280
 CIS cryofocusing temperature (°C)−30
 CIS 2nd desorption temperature (°C)300
 2nd desorption holding time (min)5
 Cryofocusing liquidLiquid nitrogen (N2)

GC parameters
 GC modelAgilent 7890A GC
 Split ratio20 : 1
 ColumnHP-5MS (60 m Length, 0.25 mm I.D., 0.250  m film thickness)
 Oven temperature program40°C, hold for 2 min
8°C/min to 180°C, hold for 2 min
10°C/min to 250°C, hold for 1 min
15°C/min to 300°C, hold for 5 min
 Run time (min)37.83

MS parameters
 MS modelAgilent 5975C inert XL MSD with triple-axis detector
 Electron ionization voltage (eV)70
 Quadrupole temperature (°C)150
 Source temperature (°C)230
 Mass modeFull scan and SIM (selected-ion monitoring),
 Mass range (m/z)35~550 in full scan
45, 47, and 75 in SIM (for TMSOH)