Table 2. HPLC gradient conditions for retinol and β-carotene simultaneous analyses

Time (min)	A1) (%)	B2) (%)
0	75	25
8	75	25
50	10	90
55	10	90
57	75	25
65	75	25

Mobile phase A: methanol:butanol:water=89.5:10:0.5 (v/v/v).
Mobile phase B: methanol:butanol:water=60:10:30 (v/v/v).