Lycopene chromatography

Kucuk, O. et al.. Effects of lycopene supplementation in patients with localized prostate cancer, Exp. Biol. Med. (Maywood), 227, 881, 2002. van Breemen, R.B. et al.. Liquid chromatography-mass spectrometry of cis- and all-trans-lycopene in human serum and prostate tissue after dietary supplementation with tomato sauce, J. Agric. Food Chem., 50, 2214, 2002. 

Ferruzzi, M.G. et ah. Analysis of lycopene geometrical isomers in biological microsamples by liquid chromatography with coulometric array detection, J. Chromatogr. B Biomed. ScL Appl. 760, 289, 2001. 

Wei, Y. et ah. Application of analytical and preparative high-speed counter-current chromatography for separation of lycopene from crude extract of tomato paste, J. Chromatogr. A, 929, 169, 2001. 

Reversed-phase liquid chromatography shape-recognition processes are distinctly limited to describe the enhanced separation of geometric isomers or structurally related compounds that result primarily from the differences between molecular shapes rather than from additional interactions within the stationary-phase and/or silica support. For example, residual silanol activity of the base silica on nonend-capped polymeric Cis phases was found to enhance the separation of the polar carotenoids lutein and zeaxanthin [29]. In contrast, the separations of both the nonpolar carotenoid probes (a- and P-carotene and lycopene) and the SRM 869 column test mixture on endcapped and nonendcapped polymeric Cig phases exhibited no appreciable difference in retention. The nonpolar probes are subject to shape-selective interactions with the alkyl component of the stationary-phase (irrespective of endcapping), whereas the polar carotenoids containing hydroxyl moieties are subject to an additional level of retentive interactions via H-bonding with the surface silanols. Therefore, a direct comparison between the retention behavior of nonpolar and polar carotenoid solutes of similar shape and size that vary by the addition of polar substituents (e.g., dl-trans P-carotene vs. dll-trans P-cryptoxanthin) may not always be appropriate in the context of shape selectivity. 

Figure F2.4.1 Liquid chromatography/mass spectrometry (LC/MS) analysis of isomeric carotenes in a hexane extract from 0.5 ml human serum. Positive ion electrospray ionization MS was used on a quadrupole mass spectrometer with selected ion monitoring to record the molecular ions of lycopene, p-carotene, and a-carotene at m/z (mass-to-charge ratio) 536. A C30 HPLC column was used for separation with a gradient from methanol to methyl-ferf-butyl ether. The a -trans isomer of lycopene was detected at a retention time of 38.1 min and various c/ s isomers of lycopene eluted between 27 and 39 min. The all-frans isomers of a-carotene and P-carotene were detected at 17.3 and 19.3 min, respectively.

Fang L, Pajkovic N, Wang Y, Gu C and van Breemen RB, Quantitative analysis of lycopene isomers in human plasma using high-performance liquid chromatography-tandem mass spectrometry. Anal Chem 75 812-817 (2003). 

O. Froescheis, S. Moalli, H. Liechti, and J. Bausch, Determination of lycopene in tissues and plasma of rats by normal-phase high-performance liquid chromatography with photometric detection, J. Chromatogr. B 739 (2000), 291-299. 

Thin-Layer Chromatography Analysis of Analgesics and Isolation of Lycopene from Tomato Paste... 

Immediately cork the tube filled with nitrogen and then add a drop or two of dichloromethane to dissolve the pigments for TLC analysis. Carry out the analysis without delay by spotting the mixture on a TLC plate about 1 cm from the bottom and 8 mm from the edge. Make one spot concentrated by repeatedly touching the plate, but ensure that the spot is as small as possible—less than 1.0 mm in diameter. The other spot can be of lower concentration. Develop the plate with 70 30 hexane acetone. With other plates try cyclohexane and toluene as eluents and also hexane/ethanol mixtures of various compositions. The container in which the chromatography is carried out should be lined with filter paper that is wet with the solvent so the atmosphere in the container will be saturated with solvent vapor. On completion of elution, mark the solvent front with a pencil and outline the colored spots. Examine the plate under the uv light. Are any new spots seen Report colors and i /values for all of your spots, and identify each as lycopene, carotene, chlorophyll, or xanthophyll. 

The colored hydrocarbons are materials for an interesting experiment in thin-layer chromatography (Chapter 9), but commercial samples are extremely expensive and subject to deterioration on storage. The isolation procedure in this chapter affords amounts of pigments that are un-weighable, except on a microbalance, but more than adequate for the thin-layer chromatography experiment. It is suggested that half the students isolate lycopene and the other half j8-carotene. 

Lycopene [502-65-8] M 536.9, m 172-173°, e ifm 2250 (446nm), 3450 (472nm), 3150 (505nm) in pet ether. Crystd from CS2/MeOH, diethyl ether/pet ether, or acetone/pet ether, and purified by column chromatography on deactivated alumina, CaC03, calcium hydroxide or magnesia. Stored in the dark, in an inert atmosphere. 

T Hagiwara, T Yasuno, K Funayama, SJ Suzuki. Determination of lycopene, alpha-carotene and beta-carotene in serum by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry with selected-ion monitoring. J. Chromatogr B Biomed 708 67—73, 1998. 

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