Carotene is a type of carotenoid that has vitamin A action in the human bodies. C18U 2D was used to analyze α-carotene and β-carotene. The analysis was completed within 10 minutes. α-carotene and β-carotene were detected in a commercial 100 % carrot juice.

Sample pretreatment for carrot juice
1) Weigh 1-g of carrot juice into a 50-mL centrifuge tube.
2) Add 10 mL of 3 % pyrogallol-ethanol solution and 5-g of anhydrous sodium sulfate.
3) After leaving it for 5 minutes to permeate, centrifuge at 1500 rpm for 5 minutes.
4) Transfer upper layer to a 100-mL volumetric flask.
5) Repeat steps 2) to 4) on lower layer
6) Add 3-% pyrogallol-ethanol solution to fill the volumetric flask (100 mL).
7) Transfer 5 mL of the mixture into a 50-mL centrifuge tube.
8) Add 11.5 mL of 1-% sodium chloride solution, 3 mL of isopropyl alcohol, and 7.5 mL of 9:1 (v/v) hexane-ethyl acetate mixture.
9) After leaving it for 5 minutes to permeate, centrifuge at 1500 rpm for 5 minutes.
10) Transfer upper layer to a 50-mL volumetric flask.
11) Repeat steps 8) to 10) on lower layer
12) Remove solvent under reduced pressure
13) Dissolve the remaining solid in 5-mL ethanol
14) Filer using a 0.45-µm membrane filter and use it as an injection sample

Sample : 5 µL
Standard
1. α-Carotene 5 µg/mL
2. β-Carotene 5 µg/mL
(in Acetone)

Carrot juice
1. α-Carotene
2. β-Carotene

Column       : Shodex C18U 2D (2.0 mm I.D. x 150 mm)
Eluent       : CH3CN/CH3OH=1/1
Flow rate    : 0.4 mL/min
Detector     : PDA (455 nm)
Column temp. : 40 °C