Table 1. Liquid chromatography (LC) conditions for vitamin B₁₂

Parameter		Condition
Column		UG 120 C18 4.6×250 nm, 5 μm, Shimadzu
Detector		UV 361 nm
Mobile phase	A: waterB: Acetonitrile gradient system	Time (min)	Solvent (A) %	Solvent (B) %
		0	100	0
		3.5	75	25
		11.0	65	35
		19.0	90	10
		20.0	100	0
		26.0	100	0
Flow rate		1.0 mL/min
Column temperature		35°C
Run time		25 min
Injection volume		50 μL