Epoxycarotenoids esters analysis in intact orange juices using two‐dimensional comprehensive liquid chromatography

Abstract

In this work, the native carotenoid pattern of different orange juices was studied by LC x LC-DAD/APCI-IT-TOF-MS for the first time. Special attention was given to the epoxycarotenoids components. It has been already proposed that the relative proportions and composition of these epoxycarotenoids can be used to estimate the age and freshness of an orange juice. Re-arrangements from 5,6- to 5,8-epoxides can occur with time, partially due to the natural acidity of the juices. Thus, the study of these carotenoids in their intact form, that is, esterified with fatty acids, is of great interest. Besides, other free carotenoid and carotenoids esters were identified in seven different monovarietal orange juices and a commercial orange juice. Moreover, the higher separation power of the present LC x LC approach allowed a clearer identification of the compounds contained in the sample compared to the more commonly used approach which uses C(30) stationary phases in conventional LC, thanks to the attainment of clearer MS spectra due to the higher resolution and separation degree obtained in LC x LC. This method could also be used to establish authenticity markers among orange varieties that could be potentially used to prevent or detect adulterations or to establish ripeness indexes.

Free carotenoid and carotenoid ester composition in native orange juices of different varieties

“…The compounds were characterised in terms of UV/Vis and MS spectra and their content in each sample analysed (table I). The identification was carried out by combining the information provided by the two detectors employed (i.e., DAD and MS detectors), the retention times of the available standards, and the identifications previously carried out in our work on the analysis of the native carotenoid composition in orange juice using C 30 columns [34] and also in our study on the application of a comprehensive liquid chromatographic method in the separation of epoxycarotenoid esters in orange juices [35]. The quantitative data were obtained by using the method of external standard calibration after the construction of the calibration curves.…”

Two-step cleanup procedure for the identification of carotenoid esters by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry

“…On the other hand, no pre-treatment was carried for analysis of carotenoid esters from orange juices [8] and from tropical fruits from Panama [9]. Alternatively, two-dimensional comprehensive liquid chromatography coupled to mass spectrometry can be used to improve the separation of the carotenoids in their native form, facilitating the identification [10,11].…”

Stop-flow comprehensive two-dimensional liquid chromatography combined with mass spectrometric detection for phospholipid analysis

“…Therefore, in this work, for the 1 D separations, a 15 cm-long, silica HILIC column, built on the Fused core technology, was used. Such a stationary phase was successfully employed in previous researches, either in one-dimensional or multidimensional LC × LC set-ups [8,[25][26][27][28][29][30][31]. Fig.…”