Table 2. Specification and operating condition of GC for butyric acid analysis

Instrument	GC-FID
Column	SP-2560 (Supelco, 100 m × 0.2 mm ID, 0.2 μm film)
Detector	Flame ionization detector
Oven temperature	100°C (2 min) - 4°C/min – 230°C (20 min)
Injection temperature	230°C
Detector temperature	250°C
Carrier gas	He
Column flow	1.5 mL/min
Injection volumn	1.0 uL
Split ratio	50:1

GC, gas chromatography; FID, Flame ionization detector.