Carotenoids: separation methods applicable to biological samples

Simple method for the extraction and reversed-phase high-performance liquid chromatographic analysis of carotenoid pigments from red yeasts (Basidiomycota, Fungi)

A simple method for the extraction of carotenoid pigments from frozen wet cells of red yeasts (Basidiomycota) and their analysis by reversed-phase HPLC using a C(18) column and a water/acetone solvent system is described. Typical red yeast carotenoids belonging to an oxidative series from the monocyclic gamma-carotene to 2-hydroxytorularhodin and from the bicyclic beta-carotene to astaxanthin were separated. Pigment identity was confirmed by LC-atmospheric pressure chemical ionisation (APCI) mass spectrometry using similar chromatographic conditions.

Quantification of 3R,3′R-zeaxanthin in plant derived food by a diastereomeric dilution assay applying chiral high-performance liquid chromatography

For quantification of 3R,3'R-zeaxanthin in plant derived food, a new diastereomeric dilution assay (DIDA) was developed using chiral high-performance liquid chromatography coupled to diode-array detection (HPLC/DAD). As diastereomeric internal standard (I.S.), 3R,3'S-(meso)-zeaxanthin was applied. DIDA showed sufficient sensitivity with low limits of detection and quantification (18 microg100 g(-1) and 45 microg 100 g(-1)), a good inter-assay coefficient of variation (2.4%), determined by analysis of a certified BCR reference material, and a good recovery (94.7%). To prove the applicability of DIDA, various plant materials were analyzed, showing that DIDA is highly advisable if saponification is applied during work-up to hydrolyze xanthophyll esters.

Profiling of carotenoids in tomato juice by one- and two-dimensional NMR

Epidemiological data have shown a link between dietary intake of tomatoes and tomato products (rich in carotenoids) and a decreased risk of chronic diseases. The carotenoid profile in tomato products depends on tomato variety as well as the thermal conditions used in processing. The final carotenoid profile may affect the bioaccessibility and bioavailability of these biomolecules. Therefore, nondestructive, reliable methods are needed to characterize the structural and stereochemical variation of carotenoids. CDCl(3) rapid extraction was used to extract carotenoids from tomato juice as an alternative rapid procedure that minimizes solvents and time consumption prior to NMR analysis. The profile of these biomolecules was characterized by application of high-resolution multidimensional NMR techniques using a cryogenic probe. The combination of homonuclear and heteronuclear two-dimensional NMR techniques served to identify (all-E)-, (5Z)-, (9Z)-, and (13Z)-lycopene isomers and other carotenoids such as (all-E)-beta-carotene and (15Z)-phytoene dissolved in the extracted lipid mixture. The use of one-dimensional NMR enabled the rapid identification of lycopene isomers, thereby minimizing further isomerization of (all-E)-lycopene as compared to HPLC data. On the basis of the assignments accomplished, the carotenoid profile of typical tomato juice was successfully determined with minimal purification procedures.

Simultaneous quantification of α-tocopherol and four major carotenoids in botanical materials by normal phase liquid chromatography–atmospheric pressure chemical ionization-tandem mass spectrometry

A rapid and sensitive method for the simultaneous quantification of alpha-tocopherol, beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin in botanical materials has been developed using normal phase liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (NP-LC-APCI-MS/MS). A systematic extraction procedure for different botanical materials was described and the extraction solvents were matched with normal-phase LC requirement. Quantification was performed by using the external standards and standard calibration curves were linear between 35 and 8505 ng/mL for alpha-tocopherol, 64-15,552 ng/mL for beta-carotene, 40-9720 ng/mL for beta-cryptoxanthin, 70-17,010 ng/mL for lutein and 64-15,552 ng/mL for zeaxanthin with regression coefficient r2 > 0.9996. The limits of quantification (LOQ) were 35, 64, 40, 70 and 66 ng/mL for alpha-tocopherol, beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin, respectively.

Determination of carotenoids and all-trans-retinol in fish eggs by liquid chromatography–electrospray ionization–tandem mass spectrometry

A novel method was developed for the combined determination of carotenoids and retinoids in fish eggs, which incorporates prior analyte isolation using liquid-liquid partitioning to minimize analyte degradation, and fraction analysis using high-performance liquid chromatography-electrospray (positive)-quadrupole mass spectrometry (LC-ESI(+)-MS; SIM or MRM modes). Eggs from Chinook salmon (Oncorhynchus tshawytscha) were used as the model fish egg matrix. The methodology was assessed and validated for beta-carotene, lutein, zeaxanthin, and beta-cryptoxanthin (molecular ion radicals [M](+)), canthaxanthin and astaxanthin ([M+Na](+) adducts) and all-trans-retinol ([(M+H)-H(2)O](+)). Using replicate egg samples (n=5) spiked with beta-cryptoxanthin and beta-carotene before and after extraction, matrix-sourced ESI(+) enhancement was observed as evidenced by comparable %matrix effect and %process efficiency values for beta-cryptoxanthin and beta-carotene of 114-119%. In aquaculture-raised eggs from adult Chinook salmon astaxanthin, all-trans-retinol, lutein and canthaxanthin were identified and determined at concentrations of 4.12, 1.06, 0.12 and 0.45 microg/g (egg wet weight), respectively. To our knowledge, this is the first report on a method for LC-MS determination of carotenoids and retinoids in a fish egg matrix, and the first carotenoid-specific determination in any fish egg sample.