The oily product ZANTHIN consists of natural astaxanthin, which is manufactured from the microalgae Haematococcus pluvialis by supercritical CO(2) extraction. An HPLC method was developed to separate all of the components of the complex astaxanthin extract using a C(30) column. The separation resulted in different isomers of astaxanthin accompanied by two other carotenoids. The main component consisted of astaxanthin singly esterified with several different fatty acids. C18:3, C18:2, C18:1 and C16:0 were identified as the most commonly occurring fatty acids. Doubly esterified astaxanthin was also found, although in lower concentrations compared to singly esterified astaxanthin. After performing a detailed fatty acid analysis by GC-MS, the peaks from the extract were assigned via HPLC-MS. A trans to cis transmutation of the all-trans compound was performed by thermal treatment in order to obtain an enrichment of cis isomers as the basis for unambiguous identification via NMR experiments. The all-trans as well as the 9- and 13-cis isomers of astaxanthin were characterized in detail by UV/Vis, (1)H, and (1)H,(1)H COSY NMR spectroscopy.

The identification of volatile cis/trans-stereoisomers was accomplished by employing a hyphenated GC-NMR system. The chromatographic and spectroscopic conditions were optimized with respect to the (1)H NMR detection. A special processing technique was developed to handle the recorded NMR spectra in the gas phase with very low sample amounts. The processed stopped-flow (1)H NMR spectra of the investigated chromatographic peaks unequivocally revealed the structure of the corresponding compounds.

An overview upon modern analytical techniques for the isolation, separation, and structural identification of the essential bioactive carotenoid bixin is given. Isolation from biological matrices is performed by matrix solid phase dispersion (MSPD). The extract is separated with shape‐selective C30 columns. Structural assignment of the separated compounds is done by online LC‐MS and capillary HPLC‐NMR.

This review deals with the current status of important separation techniques using capillary NMR detection. The advantages and disadvantages of the different hyphenated methods are discussed referring to a specific application. The use of Capillary-HPLC-NMR is demonstrated on an identification method of two bixin stereoisomers. The huge advantages using an HPLC-SPE-NMR method for structure determination are explained and discussed. Furthermore, two uncommon coupling techniques such as CE-NMR and GC-NMR are described in this review article.

A new method using phase optimized LC (POPLC) for the analysis of steroids is described. The retention factors and the theoretical plate numbers of different steroids were determined for four different stationary phases. Based on these values, an optimal stationary phase composition and the resultant chromatogram have been calculated by an optimization software and compared to the measured data. It is demonstrated that these predicted data show only little differences to the experimental results. Furthermore, it is shown that the overall selectivity of the optimal stationary phase composition is much better than the selectivity of any individual stationary phase.

The titration of the (S)-enantiomer of omeprazole with the (R)-enantiomer in chloroform-d(1) is monitored by continuous-flow capillary microcoil (1)H NMR spectroscopy employing a microcoil with a detection volume of 1.5 µl. The observed changes of the (1)H NMR chemical shifts indicate the formation of a heterochiral (R,S) dimer of omeprazole via its sulfinyl group and the NH group of the benzimidazole ring.

Reversed-phase materials with branched and unbranched alkyl groups were prepared by modifying porous, spherical silica gel in a two-step reaction-immobilization of a trifunctional alkoxysilane (3-glycidoxypropyltrimethoxysilane) on the silica surface followed by reaction with a branched and an unbranched octanoic acid. The chromatographic sorbents were characterized by solid-state (29)Si and (13)C NMR spectroscopy. The chromatographic behaviour of the stationary phases was evaluated by use of a test mixture according to the Standard Reference Material 870 set from the US National Institute of Standards and Technology, in order to study the effect of branched and unbranched alkyl chains.

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