An Efficient Solid-Phase Extraction-Based Liquid Chromatography Method to Simultaneously Determine Diastereomers α-Tocopherol, Other Tocols, and Retinol Isomers in Infant Formula
Table 1
Parameters of the RP-LC method for determination of vitamin E and retinol isomers.
Analyte
RT (min)
Calibration curve
r
LOD (mg kg−1)
LOQ (mg kg−1)
Range (μg mL−1)
All-trans-retinol
6.53
y = 0.0042x − 3.00
0.9999
0.05
0.15
0.1∼5
13-cis-retinol
7.09
y = 0.0046x − 0.36
1.0000
0.05
0.15
0.01∼0.5
9-cis-retinol
5.97
y = 0.0041x − 1.43
1.0000
0.05
0.15
0.01∼0.5
DL-α-tocopherol(a)
33.34/35.10
y = 0.0006x − 74.28
0.9998
0.4
1.2
2∼100
D-α-tocopherol
33.34
y = 0.0006x − 119.01
0.9998
0.4
1.2
0.5∼25
D-β-tocopherol
31.93
y = 0.0002x − 10.63
0.9999
0.4
1.2
0.5∼25
D-γ-tocopherol
30.84
y = 0.0001x + 49.20
0.9999
0.4
1.2
0.5∼25
D-δ-tocopherol
27.99
y = 0.0001x + 10.72
0.9999
0.4
1.2
0.5∼25
D-α-tocotrienol
26.92
y = 0.0006x + 108.41
0.9999
0.4
1.2
0.5∼25
D-β-tocotrienol
24.32
y = 0.0002x + 7.62
0.9996
0.4
1.2
0.5∼25
D-γ-tocotrienol
22.29
y = 0.0002x + 47.58
0.9999
0.4
1.2
0.5∼25
D-δ-tocotrienol
18.30
y = 0.0001x − 12.00
0.9999
0.4
1.2
0.5∼25
(a) Two ideal peaks appeared in retention time (RT) of 33.34 min and 35.10 min, within the approximate peak area.
