Separation and quantitative analysis of some carotenoid fatty acid esters of fruits by liquid chromatography.

The adsorption and partition properties of several fatty acid esters of capsanthin, capsorubin, beta-cryptoxanthin, lutein, violaxanthin and beta-citraurin isolated from fruits were studied by normal-phase (silica) and reversed-phase (octadecylsilane) liquid chromatography using Sudan 1 as internal standard. The separation on a normal phase was based on the functional group of the carotenoids and individual esters of the same carotenoid did not resolve. The separation on a reversed phase was more dependent on the number of acyl carbons than the functional group, and individual esters of the same carotenoid differing only two acyl carbons were separated with a resolution of 3. There was a linear relationship between number of acyl carbons and retention times of the same carotenoid on reversed phase. The separation on a normal phase was the reverse of that on a reversed phase, and a combination of normal-phase followed by reversed-phase chromatography was used for the separation of esters with the same or close retention times.