Analysis of palm oil carotenoids by HPLC with diode-array detection.
Palm oil carotenoids are analyzed by nonaqueous reversed-phase high-performance liquid chromatography (NARP-HPLC) with UV/vis diode-array detection. Isocratic elution with 60% acetonitrile/35% methanol/5% methylene chloride at 2 mL/min on a 25-cm C18 column results in an analysis time of 30 min. Identification is made through absorption spectra and chromatographic elution behaviors, for example, polyenic pi conjugation, dipole moment of end-groups, and oxygen function on the chromophores. At least 12 carotenoids are identified with alpha- and beta-carotene as the dominant carotenoids (1:2 ratio). Several mono- and di-epoxides of alpha- and beta-isomers and hydrocarbon carotenes are found, including the UV-absorbing phytoene identified by spectral substraction. cis-Isomerization is found and discussed in the light of spectral evidence. The effect of saponification time on the amount of extracted carotenes is investigated. Quantitation results in a combined alpha- and beta-carotene concentration of at least 506 ppm. The detection limit for beta-carotene is 31 ng.
Ng
J H
JH
Department of Chemistry, University of Massachusetts, Amherst 01003.
Tan
B
B
D002338:Carotenoids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D000073878:Palm Oil; D010938:Plant Oils / Q000032:analysis*; D013237:Stereoisomerism
D010938:Plant Oils; D002338:Carotenoids; D000073878:Palm Oil