Analysis of native carotenoid composition in orange juice using C-30 columns in tandem

In the present contribution, a novel analytical approach based on using serial coupled conventional LC columns is proposed to the study of the native carotenoid composition of orange juice. The great difficulties that are found when analyzing complex carotenoid samples, due to the high natural variability of these com- pounds as well as to the presence of carotenoid esters are well documented. To over- come some of these limitations, we have developed a methodology including the study of both the saponified and the intact sample by means of two different LC- DAD/APCI-MS methods. The increase in the resolution and separation power obtained when using two serial coupled C30 columns is demonstrated, and signifi- cant increases in peak capacity have been achieved. By using this new methodology, 44 different carotenoids have been tentatively identified. Among them, several vio- laxanthin diesters have been directly identified in orange juice for the first time. The main carotenoids in orange juice were violaxanthin, lutein, luteoxanthin, 9-cis- antheraxanthin, and b-cryptoxanthin. Some of them were found in both their free and esterified forms. To the best of our knowledge, this is the first application of serial couplings of C30 columns for the identification of the native carotenoid com- position of natural matrices.