Table 3. Four-Assay Panel of GC Methods (Nonpolar Column).

instrument	TD-GC-TOF-MS (nonpolar column)
urine volume	2 mL	0.25 mL	2 mL	0.25 mL
GC column flow	1.6 mL/min	1.6 mL/min	2 mL/min	2 mL/min
GC oven gradients	initial temperature at 35 °C hold for 4.5 min, ramp to 300 °C at 8 °C/min hold for 4 min		initial temperature at 35 °C hold for 4.5 min, ramp to 300 °C at 10 °C/min hold for 4 min
GC cycle time	44 min	44 min	37 min	37 min
no. of VOCs	154	85	167	103