Carotenoids separation

With this mobile phase colour compounds and carotenoids separated with 15 ml of chloroform (first fraction) and the second fraction with 20ml chloroform contained total petroleum hydrocarbons. At the end Spectrofluorophotometry was employed for quantification of analytes. 

A variety of mobile phases have been employed for carotenoid separation by reversed phase HPLC. Most are based on MeOH or acetonitrile, with the addition of CH2CI2, THF, methyl-tert-butyl ether (MTBE), acetone, or EtOAc. In general, recoveries of carotenoids are higher with methanol-based systems compared to acetonitrile-based ones." ... 

Considering that each stationary phase has a different mechanism of separation, the analyst should apply the most suitable phase for a particular carotenoid separation, not forgetting that it is very useful to look for previous experiences among the several examples available in the literature and that it is also possible to find different solutions for the same problem. 

Although some normal phase methods have been used, the majority of carotenoid separations reported in the literature were carried out by reversed phase HPLC. Among the Cjg columns employed for determination of complete carotenoid compositions in foods, the polymeric Vydac brand is preferably used for separation of cis isomers. Several examples of different C,g columns and mobile phases are cited in the literature, but not aU carotenoids are baseline separated in most systems. Table 6.2.1 shows some examples employing different brands of Cjg columns." Acetonitrile did not improve selectivity toward separation of carotene isomers in a Vydac 201TP column and resolution was strongly dependent on the Vydac column lot. ... 

Phases of extended length (C30) have been utilized for the separation of larger-size constrained solutes, such as carotenoids and steroids [27-29,93,106,107]. Apractical limit of alkyl chain length of C34 to C36 is imposed by the commonly employed silan-ization chemistry techniques [106]. Immobilization of longer alkyl stationary phases has been achieved through the use of poly(ethylene-co-acrylic acid) materials for use in carotenoid separations [27,28,93]. Rimmer et al. [28] have recently compared the selectivity of both alkyl and poly(ethylene-co-acrylic acid) stationary phases on the basis of separations of carotenoids in food matrices (Figure 5.12), in addition to mixtures of tocopherols and PAHs. 

Basic Protocol 1 Isocratic Carotenoid Separation Using Wide-Pore,... 

ISOCRATIC CAROTENOID SEPARATION USING WIDE-PORE,... 

ISOCRATIC CAROTENOID SEPARATION CAPABLE OF SIMULTANEOUS SEPARATION OF RETINOL AND TOCOPHEROL USING SPHERISORB ODS2... 

Carotenoid separations can be accomplished by both normal- and reversed-phase HPLC. Normal-phase HPLC (NPLC) utilizes columns with adsorptive phases (i.e., silica) and polar bonded phases (i.e., alkylamine) in combination with nonpolar mobile phases. In this situation, the polar sites of the carotenoid molecules compete with the modifiers present in the solvent for the polar sites on the stationary phase therefore, the least polar compounds... 

Craft, N.E. 2001. Chromatographic techniques for carotenoid separation. In Current Protocols in Food Analytical Chemistry (Wrolstad, R.E., Ed.). John Wiley Sons Inc., New York, pp. F2.3.1-F2.3.12. 

Su, Q. Rowley, K.G. Balazs, N.D.H. 2002. Carotenoids Separation methods appli-eable to biological samples. J. Chromatogra A 781 393-418. 

Separation and Assay. H.p.l.c. methods have been described for the determination of chloroplast pigments,phytoplankton pigments,and provitamin A carotenoids in tomatoes.Other chromatographic procedures have been devised for the separation of Capsicum carotenoids and chloroplast pigments from tobacco mutants, " and methods for the high-speed video-densitometric determination of carotenoids separated by t.l.c., and for the dual assay of carotenoids and vitamin A in human liver have been reported. H.p.l.c. has been used for the separation of cis-trans-isomers of retinal, retinol and retinyl... 

Introduction.—This Report covers the literature published up to approximately the end of September, 1981. Few new carotenoid structures have been reported. The main advances in carotenoid chemistry have been in the stereospecific synthesis of carotenoids with chiral end-groups. Current interest in the possible use of retinoids in cancer chemotherapy has prompted the preparation of a considerable number of retinoic acid analogues. There has been no major new development in the use of physical methods but h.p.l.c. becomes more and more the method of choice for carotenoid separation, purification, and assay, and the increasing number of papers on resonance Raman spectroscopy emphasizes the potential value of this technique in the carotenoid field. 

Physical Methods.—Separation and Assay. Increasing use is being made of h.p.l.c. in the carotenoid field. This technique will clearly become the method of choice for carotenoid separation, purification, and analysis. The first papers on carotenoid h.p.l.c. have recently been published. These include a systematic study of the chromatography of model mixtures of carotenes, carotenediols, cis trans isomers, and diastereoisomers. ° Many papers report the use of h.p.l.c. 

Figure 2A. SFC-FID chromatograms of carotenoids separated on DB-17 stationary phase. See Figure 1 for key to compound structures.

The majority of carotenoid separation has been carried out with 5 pm Cl 8 spherical particles packed in a 250 x 4.6-mm column. However, shorter and narrower (narrow bore) columns, smaller particles, and C30 stationary phases are increasingly used. 

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